I have created a IDispatch based COM class with which I am able to extend the 
XSL (XPath) functions. I register my COM class with the XSL processor using 
addObject before doing the transformation. Everything works fine and behaves 
as expected.

The next thing that I want to do is to make my COM methods visible as 
extension elements. Somehow, the XSL engine refuses to accept my COM methods 
as extension elements.

I have registered all namespaces and identified my COM object as an 
extension element, eg.

<xsl:stylesheet version="1.0" xml:lang="en-US"
   xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
   xmlns:response="urn:MyResponseObject"
   extension-element-prefixes="response">

The following XSL snippet returns true:
<xsl:value-of select="element-available('xsl:for-each')"/>

The following XSL snippet returns false:
<xsl:value-of select="element-available('response:myFunc')"/>

Can anyone please assist? 

PS. I know that I can use <xsl:value-of select="response:myFunc(param)"/> to 
call methods, but this means that I have to change all my class methods to 
return  dummy (empty) strings and it makes the XSL look a little weird.