diff --git a/include/osgDB/InputStream b/include/osgDB/InputStream
index 0b0c70817..af431f46c 100644
--- a/include/osgDB/InputStream
+++ b/include/osgDB/InputStream
@@ -139,8 +139,13 @@ public:
     osg::Image* readImage(bool readFromExternal=true);
     osg::Object* readObject( osg::Object* existingObj=0 );
     osg::Object* readObjectFields( const std::string& className, osg::Object* existingObj=0);
-    
+
+    /// set an input iterator, used directly when not using InputStream with a traditional file releated stream.
+    void setInputIterator( InputIterator* ii ) { _in = ii; }
+
+    /// start reading from InputStream treating it as a traditional file releated stream, handles headers and versioning
     ReadType start( InputIterator* );
+
     void decompress();
     
     // Schema handlers
diff --git a/include/osgDB/OutputStream b/include/osgDB/OutputStream
index 275840462..21baa0fb0 100644
--- a/include/osgDB/OutputStream
+++ b/include/osgDB/OutputStream
@@ -149,7 +149,12 @@ public:
     void writeObject( const osg::Object* obj );
     void writeObjectFields( const osg::Object* obj );
     
+    /// set an output iterator, used directly when not using OutputStream with a traditional file releated stream.
+    void setOutputIterator( OutputIterator* oi ) { _out = oi; }
+
+    /// start writing to OutputStream treating it as a traditional file releated stream, handles headers and versioning
     void start( OutputIterator* outIterator, WriteType type );
+
     void compress( std::ostream* ostream );
     
     // Schema handlers