--- a/VSEFileSourceWriter.st	Fri Feb 13 03:02:36 2015 +0100
+++ b/VSEFileSourceWriter.st	Fri Feb 13 03:17:35 2015 +0100
@@ -115,6 +115,18 @@
     "
      self defaultClassNameTranslations
     "
+!
+
+extensionClassesSkipped
+    "for classes that do not exist in VSE"
+
+    ^ Set new
+        add:#Filename;
+        yourself
+
+    "
+     self extensionClassesSkipped
+    "
 ! !
 
 !VSEFileSourceWriter methodsFor:'initialization'!
@@ -151,12 +163,16 @@
 
     methodsToFileOut := OrderedCollection new.
     Smalltalk allClassesDo:[:eachClass |
-        eachClass instAndClassSelectorsAndMethodsDo:[:sel :mthd |
-            |mPckg|
+        (self class extensionClassesSkipped includes:eachClass) ifTrue:[
+            Transcript showCR:'skipped extension for ',eachClass name
+        ] ifFalse:[
+            eachClass instAndClassSelectorsAndMethodsDo:[:sel :mthd |
+                |mPckg|
 
-            mPckg := mthd package.
-            (mPckg = packageID and:[mPckg ~= eachClass package]) ifTrue:[
-                methodsToFileOut add:mthd.
+                mPckg := mthd package.
+                (mPckg = packageID and:[mPckg ~= eachClass package]) ifTrue:[
+                    methodsToFileOut add:mthd.
+                ]
             ]
         ]
     ].
@@ -544,10 +560,10 @@
 !VSEFileSourceWriter class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libbasic3/VSEFileSourceWriter.st,v 1.16 2015-02-13 01:54:12 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic3/VSEFileSourceWriter.st,v 1.17 2015-02-13 02:17:35 cg Exp $'
 !
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic3/VSEFileSourceWriter.st,v 1.16 2015-02-13 01:54:12 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libbasic3/VSEFileSourceWriter.st,v 1.17 2015-02-13 02:17:35 cg Exp $'
 ! !