         this.srcFunc = srcFunc;
         this.destFunc = destFunc;
         this.destString = destString;
+        this.srcString = srcString;
+
+        if (this.srcFunc == null)
+        {
+            this.srcFunc = defaultSrcFunc;
+        }
 
         if (this.destFunc == null)
         {

     *  @productversion Flex 3
     */
    mx_internal var destString:String;

	/**
	 * 	@private

     *  @productversion Flex 3
     */
    public function Binding(document:Object, srcFunc:Function,
						    destFunc:Function, destString:String,
							srcString:String = null)
    {
		super();

