diff --git a/configuredialog.cpp b/configuredialog.cpp
index 5ac23fbdf..2a95764a5 100644
--- a/configuredialog.cpp
+++ b/configuredialog.cpp
@@ -2138,8 +2138,8 @@ void AppearancePage::ReaderTab::readCurrentFallbackCodec()
   bool found = false;
   for( ; it != end; ++it)
   {
-    const QString encoding = KGlobal::charsets()->encodingForName(*it);
-    if ( encoding == "ISO 8859-15" )
+    const QString encoding = KMMsgBase::encodingForName(*it);
+    if ( encoding == "ISO-8859-15" )
         indexOfLatin9 = i;
     if( encoding == currentEncoding )
     {
@@ -2167,7 +2167,7 @@ void AppearancePage::ReaderTab::readCurrentOverrideCodec()
   int i = 0;
   for( ; it != end; ++it)
   {
-    if( KGlobal::charsets()->encodingForName(*it) == currentOverrideEncoding )
+    if( KMMsgBase::encodingForName(*it) == currentOverrideEncoding )
     {
       mOverrideCharsetCombo->setCurrentIndex( i );
       break;
@@ -2211,11 +2211,11 @@ void AppearancePage::ReaderTab::save() {
 
   GlobalSettings::self()->setCollapseQuoteLevelSpin( mCollapseQuoteLevelSpin->value() );
   GlobalSettings::self()->setFallbackCharacterEncoding(
-      KGlobal::charsets()->encodingForName( mCharsetCombo->currentText() ) );
+      KMMsgBase::encodingForName( mCharsetCombo->currentText() ) );
   GlobalSettings::self()->setOverrideCharacterEncoding(
       mOverrideCharsetCombo->currentIndex() == 0 ?
         QString() :
-        KGlobal::charsets()->encodingForName( mOverrideCharsetCombo->currentText() ) );
+        KMMsgBase::encodingForName( mOverrideCharsetCombo->currentText() ) );
 }
 
 
diff --git a/kmcomposewin.cpp b/kmcomposewin.cpp
index b9efcf757..0b0c4a089 100644
--- a/kmcomposewin.cpp
+++ b/kmcomposewin.cpp
@@ -2245,7 +2245,7 @@ void KMComposeWin::setCharset( const QByteArray &aCharset, bool forceDefault )
         ++it, i++ ) {
     if (i > 0 && ((mCharset == "us-ascii" && i == 1) ||
                   (i != 1 && KGlobal::charsets()->codecForName(
-                                                               KGlobal::charsets()->encodingForName(*it))
+                                     KGlobal::charsets()->encodingForName(*it))
                    == KGlobal::charsets()->codecForName(mCharset))))
       {
         mEncodingAction->setCurrentItem( i );
@@ -2470,7 +2470,7 @@ void KMComposeWin::slotInsertFile()
   {
     KConfig *config = KMKernel::config();
     KConfigGroup group( config, "Composer" );
-    QString encoding = KGlobal::charsets()->encodingForName(encodingStr).toLatin1();
+    QString encoding = KMMsgBase::encodingForName(encodingStr).toLatin1();
     QStringList urls = group.readEntry( "recent-urls", QStringList() );
     QStringList encodings = group.readEntry( "recent-encodings", QStringList() );
     // Prevent config file from growing without bound
@@ -2534,8 +2534,7 @@ void KMComposeWin::slotSetCharset()
   }
   mAutoCharset = false;
 
-  mCharset = KGlobal::charsets()->encodingForName( mEncodingAction->
-                                                   currentText() ).toLatin1();
+  mCharset = KMMsgBase::encodingForName( mEncodingAction->currentText() ).toLatin1();
 }
 
 //-----------------------------------------------------------------------------
diff --git a/kmmsgbase.cpp b/kmmsgbase.cpp
index 3e1d3d834..1ec31f65d 100644
--- a/kmmsgbase.cpp
+++ b/kmmsgbase.cpp
@@ -399,6 +399,20 @@ QStringList KMMsgBase::supportedEncodings(bool usAscii)
   return encodings;
 }
 
+//-----------------------------------------------------------------------------
+QString KMMsgBase::encodingForName( const QString &descriptiveName )
+{
+  QString encoding = KGlobal::charsets()->encodingForName( descriptiveName );
+
+  // According to http://www.iana.org/assignments/character-sets, uppercase is
+  // prefered in MIME headers
+  if ( encoding.toUpper().contains( "ISO " ) ) {
+    encoding = encoding.toUpper();
+    encoding.replace( "ISO ", "ISO-" );
+  }
+  return encoding;
+}
+
 //-----------------------------------------------------------------------------
 QByteArray fallbackCharsetForRFC2047Decoding( const QByteArray &prefCharset )
 {
diff --git a/kmmsgbase.h b/kmmsgbase.h
index 22c1dd3c6..539e1d163 100644
--- a/kmmsgbase.h
+++ b/kmmsgbase.h
@@ -259,6 +259,14 @@ public:
   /** Return a list of the supported encodings */
   static QStringList supportedEncodings(bool usAscii);
 
+  /**
+   * Drop-in replacement for KCharsets::encodingForName(). The problem with
+   * the KCharsets function is that it returns "human-readable" encoding names
+   * like "ISO 8859-15" instead of valid encoding names like "ISO-8859-15".
+   * This function fixes this by replacing whitespace with a hyphen.
+   */
+  static QString encodingForName( const QString &descriptiveName );
+
   /** Copy all values from other to this object. */
   void assign(const KMMsgBase* other);
 
diff --git a/kmreaderwin.cpp b/kmreaderwin.cpp
index abab20842..a0d6104ef 100644
--- a/kmreaderwin.cpp
+++ b/kmreaderwin.cpp
@@ -1118,7 +1118,7 @@ void KMReaderWin::setOverrideEncoding( const QString & encoding )
       QStringList encodings = mSelectEncodingAction->items();
       int i = 0;
       for ( QStringList::const_iterator it = encodings.begin(), end = encodings.end(); it != end; ++it, ++i ) {
-        if ( KGlobal::charsets()->encodingForName( *it ) == encoding ) {
+        if ( KMMsgBase::encodingForName( *it ) == encoding ) {
           mSelectEncodingAction->setCurrentItem( i );
           break;
         }
@@ -1158,7 +1158,7 @@ void KMReaderWin::slotSetEncoding()
   if ( mSelectEncodingAction->currentItem() == 0 ) // Auto
     mOverrideEncoding.clear();
   else
-    mOverrideEncoding = KGlobal::charsets()->encodingForName( mSelectEncodingAction->currentText() );
+    mOverrideEncoding = KMMsgBase::encodingForName( mSelectEncodingAction->currentText() );
   update( true );
 }