diff --git a/taglib/ape/apefile.cpp b/taglib/ape/apefile.cpp
index 41341b86..b3da1379 100644
--- a/taglib/ape/apefile.cpp
+++ b/taglib/ape/apefile.cpp
@@ -131,12 +131,9 @@ void APE::File::removeUnsupportedProperties(const StringList &properties)
 
 PropertyMap APE::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasAPE)
-    return d->tag.access<APE::Tag>(ApeAPEIndex, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(ApeID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<APE::Tag>(ApeAPEIndex, true)->setProperties(properties);
+  if(d->hasID3v1)
+    d->tag.access<ID3v1::Tag>(ApeID3v1Index, false)->setProperties(properties);
+  return d->tag.access<APE::Tag>(ApeAPEIndex, true)->setProperties(properties);
 }
 
 APE::Properties *APE::File::audioProperties() const
diff --git a/taglib/ape/apefile.h b/taglib/ape/apefile.h
index 162f980d..cfee50da 100644
--- a/taglib/ape/apefile.h
+++ b/taglib/ape/apefile.h
@@ -128,8 +128,8 @@ namespace TagLib {
 
       /*!
        * Implements the unified property interface -- import function.
-       * As for the export, only one tag is taken into account. If the file
-       * has no tag at all, APE will be created.
+       * Creates an APEv2 tag if necessary. A pontentially existing ID3v1
+       * tag will be updated as well.
        */
       PropertyMap setProperties(const PropertyMap &);
 
diff --git a/taglib/flac/flacfile.cpp b/taglib/flac/flacfile.cpp
index cb1cd5ce..e0faa18d 100644
--- a/taglib/flac/flacfile.cpp
+++ b/taglib/flac/flacfile.cpp
@@ -163,14 +163,7 @@ void FLAC::File::removeUnsupportedProperties(const StringList &unsupported)
 
 PropertyMap FLAC::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasXiphComment)
-    return d->tag.access<Ogg::XiphComment>(FlacXiphIndex, false)->setProperties(properties);
-  else if(d->hasID3v2)
-    return d->tag.access<ID3v2::Tag>(FlacID3v2Index, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(FlacID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<Ogg::XiphComment>(FlacXiphIndex, true)->setProperties(properties);
+  return d->tag.access<Ogg::XiphComment>(FlacXiphIndex, true)->setProperties(properties);
 }
 
 FLAC::Properties *FLAC::File::audioProperties() const
diff --git a/taglib/flac/flacfile.h b/taglib/flac/flacfile.h
index 3b17bc7f..cf91a21e 100644
--- a/taglib/flac/flacfile.h
+++ b/taglib/flac/flacfile.h
@@ -122,8 +122,10 @@ namespace TagLib {
 
       /*!
        * Implements the unified property interface -- import function.
-       * As with the export, only one tag is taken into account. If the file
-       * has no tag at all, a XiphComment will be created.
+       * This always creates a Xiph comment, if none exists. The return value
+       * relates to the Xiph comment only.
+       * Ignores any changes to ID3v1 or ID3v2 comments since they are not allowed
+       * in the FLAC specification.
        */
       PropertyMap setProperties(const PropertyMap &);
 
diff --git a/taglib/mpc/mpcfile.cpp b/taglib/mpc/mpcfile.cpp
index 46fa1a2c..b27fb8d2 100644
--- a/taglib/mpc/mpcfile.cpp
+++ b/taglib/mpc/mpcfile.cpp
@@ -135,15 +135,11 @@ void MPC::File::removeUnsupportedProperties(const StringList &properties)
 
 PropertyMap MPC::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasAPE)
-    return d->tag.access<APE::Tag>(MPCAPEIndex, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(MPCID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<APE::Tag>(APE, true)->setProperties(properties);
+  if(d->hasID3v1)
+    d->tag.access<APE::Tag>(MPCID3v1Index, false)->setProperties(properties);
+  return d->tag.access<APE::Tag>(MPCAPEIndex, true)->setProperties(properties);
 }
 
-
 MPC::Properties *MPC::File::audioProperties() const
 {
   return d->properties;
diff --git a/taglib/mpc/mpcfile.h b/taglib/mpc/mpcfile.h
index f3f4ac7d..887aa46d 100644
--- a/taglib/mpc/mpcfile.h
+++ b/taglib/mpc/mpcfile.h
@@ -124,8 +124,8 @@ namespace TagLib {
 
       /*!
        * Implements the unified property interface -- import function.
-       * As with the export, only one tag is taken into account. If the file
-       * has no tag at all, an APE tag will be created.
+       * Affects only the APEv2 tag which will be created if necessary.
+       * If an ID3v1 tag exists, it will be updated as well.
        */
       PropertyMap setProperties(const PropertyMap &);
 
diff --git a/taglib/mpeg/mpegfile.cpp b/taglib/mpeg/mpegfile.cpp
index d2dce48a..1091ea14 100644
--- a/taglib/mpeg/mpegfile.cpp
+++ b/taglib/mpeg/mpegfile.cpp
@@ -156,16 +156,13 @@ void MPEG::File::removeUnsupportedProperties(const StringList &properties)
   else if(d->hasID3v1)
     d->tag.access<ID3v1::Tag>(ID3v1Index, false)->removeUnsupportedProperties(properties);
 }
+
 PropertyMap MPEG::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasID3v2)
-    return d->tag.access<ID3v2::Tag>(ID3v2Index, false)->setProperties(properties);
-  else if(d->hasAPE)
-    return d->tag.access<APE::Tag>(APEIndex, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(ID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<ID3v2::Tag>(ID3v2Index, true)->setProperties(properties);
+  if(d->hasID3v1)
+    // update ID3v1 tag if it exists, but ignore the return value
+    d->tag.access<ID3v1::Tag>(ID3v1Index, false)->setProperties(properties);
+  return d->tag.access<ID3v2::Tag>(ID3v2Index, true)->setProperties(properties);
 }
 
 MPEG::Properties *MPEG::File::audioProperties() const
diff --git a/taglib/mpeg/mpegfile.h b/taglib/mpeg/mpegfile.h
index f6dc8d56..725dc19d 100644
--- a/taglib/mpeg/mpegfile.h
+++ b/taglib/mpeg/mpegfile.h
@@ -133,7 +133,7 @@ namespace TagLib {
       virtual Tag *tag() const;
 
       /*!
-       * Implements the unified property interface -- export function.
+       * Implements the reading part of the unified property interface.
        * If the file contains more than one tag, only the
        * first one (in the order ID3v2, APE, ID3v1) will be converted to the
        * PropertyMap.
@@ -143,9 +143,12 @@ namespace TagLib {
       void removeUnsupportedProperties(const StringList &properties);
 
       /*!
-       * Implements the unified tag dictionary interface -- import function.
-       * As with the export, only one tag is taken into account. If the file
-       * has no tag at all, ID3v2 will be created.
+       * Implements the writing part of the unified tag dictionary interface.
+       * In order to avoid problems with deprecated tag formats, this method
+       * always creates an ID3v2 tag if necessary.
+       * If an ID3v1 tag  exists, it will be updated as well, within the
+       * limitations of that format.
+       * The returned PropertyMap refers to the ID3v2 tag only.
        */
       PropertyMap setProperties(const PropertyMap &);
 
diff --git a/taglib/toolkit/tfile.h b/taglib/toolkit/tfile.h
index 860a889a..750efdff 100644
--- a/taglib/toolkit/tfile.h
+++ b/taglib/toolkit/tfile.h
@@ -80,12 +80,14 @@ namespace TagLib {
 
     /*!
      * Exports the tags of the file as dictionary mapping (human readable) tag
-     * names (Strings) to StringLists of tag values. Calls the according specialization
-     * in the File subclasses.
+     * names (uppercase Strings) to StringLists of tag values. Calls the according
+     * specialization in the File subclasses.
      * For each metadata object of the file that could not be parsed into the PropertyMap
      * format, the returend map's unsupportedData() list will contain one entry identifying
      * that object (e.g. the frame type for ID3v2 tags). Use removeUnsupportedProperties()
      * to remove (a subset of) them.
+     * For files that contain more than one tag (e.g. an MP3 with both an ID3v2 and an ID3v2
+     * tag) only the most "modern" one will be exported (ID3v2 in this case).
      */
     virtual PropertyMap properties() const;
 
@@ -103,9 +105,14 @@ namespace TagLib {
      * If some value(s) could not be written imported to the specific metadata format,
      * the returned PropertyMap will contain those value(s). Otherwise it will be empty,
      * indicating that no problems occured.
+     * With file types that support several tag formats (for instance, MP3 files can have
+     * ID3v1, ID3v2, and APEv2 tags), this function will create the most appropriate one
+     * (ID3v2 for MP3 files). Older formats will be updated as well, if they exist, but won't
+     * be taken into account for the return value of this function.
+     * See the documentation of the subclass implementations for detailed descriptions.
      */
     virtual PropertyMap setProperties(const PropertyMap &properties);
-
+    
     /*!
      * Returns a pointer to this file's audio properties.  This should be
      * reimplemented in the concrete subclasses.  If no audio properties were
diff --git a/taglib/trueaudio/trueaudiofile.cpp b/taglib/trueaudio/trueaudiofile.cpp
index 06879447..b584ce67 100644
--- a/taglib/trueaudio/trueaudiofile.cpp
+++ b/taglib/trueaudio/trueaudiofile.cpp
@@ -141,12 +141,9 @@ PropertyMap TrueAudio::File::properties() const
 
 PropertyMap TrueAudio::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasID3v2)
-    return d->tag.access<ID3v2::Tag>(TrueAudioID3v2Index, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(TrueAudioID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<ID3v2::Tag>(TrueAudioID3v2Index, true)->setProperties(properties);
+  if(d->hasID3v1)
+    d->tag.access<ID3v1::Tag>(TrueAudioID3v1Index, false)->setProperties(properties);
+  return d->tag.access<ID3v2::Tag>(TrueAudioID3v2Index, true)->setProperties(properties);
 }
 
 TrueAudio::Properties *TrueAudio::File::audioProperties() const
diff --git a/taglib/trueaudio/trueaudiofile.h b/taglib/trueaudio/trueaudiofile.h
index 8b8b0c05..d3f51c93 100644
--- a/taglib/trueaudio/trueaudiofile.h
+++ b/taglib/trueaudio/trueaudiofile.h
@@ -139,8 +139,8 @@ namespace TagLib {
 
       /*!
        * Implements the unified property interface -- import function.
-       * As with the export, only one tag is taken into account. If the file
-       * has no tag at all, ID3v2 will be created.
+       * Creates in ID3v2 tag if necessary. If an ID3v1 tag exists, it will
+       * be updated as well, within the limitations of ID3v1.
        */
       PropertyMap setProperties(const PropertyMap &);
 
diff --git a/taglib/wavpack/wavpackfile.cpp b/taglib/wavpack/wavpackfile.cpp
index 25495662..409ccabf 100644
--- a/taglib/wavpack/wavpackfile.cpp
+++ b/taglib/wavpack/wavpackfile.cpp
@@ -119,12 +119,9 @@ PropertyMap WavPack::File::properties() const
 
 PropertyMap WavPack::File::setProperties(const PropertyMap &properties)
 {
-  if(d->hasAPE)
-    return d->tag.access<APE::Tag>(WavAPEIndex, false)->setProperties(properties);
-  else if(d->hasID3v1)
-    return d->tag.access<ID3v1::Tag>(WavID3v1Index, false)->setProperties(properties);
-  else
-    return d->tag.access<APE::Tag>(APE, true)->setProperties(properties);
+  if(d->hasID3v1)
+    d->tag.access<ID3v1::Tag>(WavID3v1Index, false)->setProperties(properties);
+  return d->tag.access<APE::Tag>(WavAPEIndex, true)->setProperties(properties);
 }
 
 WavPack::Properties *WavPack::File::audioProperties() const
diff --git a/taglib/wavpack/wavpackfile.h b/taglib/wavpack/wavpackfile.h
index cb0dfab9..ca1c752a 100644
--- a/taglib/wavpack/wavpackfile.h
+++ b/taglib/wavpack/wavpackfile.h
@@ -118,8 +118,8 @@ namespace TagLib {
 
       /*!
        * Implements the unified property interface -- import function.
-       * As for the export, only one tag is taken into account. If the file
-       * has no tag at all, APE will be created.
+       * Creates an APE tag if it does not exists and calls setProperties() on
+       * that. Any existing ID3v1 tag will be updated as well.
        */
       PropertyMap setProperties(const PropertyMap&);
 
diff --git a/tests/test_flac.cpp b/tests/test_flac.cpp
index 3d31f33c..7f40a382 100644
--- a/tests/test_flac.cpp
+++ b/tests/test_flac.cpp
@@ -24,6 +24,7 @@ class TestFLAC : public CppUnit::TestFixture
   CPPUNIT_TEST(testRepeatedSave);
   CPPUNIT_TEST(testSaveMultipleValues);
   CPPUNIT_TEST(testDict);
+  CPPUNIT_TEST(testInvalid);
   CPPUNIT_TEST_SUITE_END();
 
 public:
@@ -231,6 +232,17 @@ public:
     CPPUNIT_ASSERT_EQUAL(String("artöst 2"), dict["ARTIST"][1]);
   }
 
+  void testInvalid()
+  {
+    ScopedFileCopy copy("silence-44-s", ".flac");
+    PropertyMap map;
+    map["HÄÖ"] = String("bla");
+    FLAC::File f(copy.fileName().c_str());
+    PropertyMap invalid = f.setProperties(map);
+    CPPUNIT_ASSERT_EQUAL(uint(1), invalid.size());
+    CPPUNIT_ASSERT_EQUAL(uint(0), f.properties().size());
+  }
+
 };
 
 CPPUNIT_TEST_SUITE_REGISTRATION(TestFLAC);
diff --git a/tests/utils.h b/tests/utils.h
index 39e15ce9..b69bfa50 100644
--- a/tests/utils.h
+++ b/tests/utils.h
@@ -7,6 +7,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/fcntl.h>
+#include <sys/stat.h>
 #endif
 #include <stdio.h>
 #include <string.h>