Stylesheet in a Xerces DOM tree?

I've got a XSL stylesheet which was preparsed by Xerces as part of the
initialization of my application. I need to be able to pass that DOM
tree to the transformer to run the transformation.
 
So far I've been unable to figure out how to get it to work.  What I
want is something like this:
 
    Xercesc_2_5::DOMElement *stylesheet;  // This was parsed earlier by
Xerces duing my program initialization
    Xercesc_2_5::DOMDocument *sourceDoc;  // The DOM document I want to
transform
    Xercesc_2_5::DOMDocument *outputDoc;  // The DOM document I want the
results placed in.
 
    XalanTransformer transformer;
 
    // transform the sourceDoc. In reality if I can only get a string
back as the output of the transform, 
    // I'm not as concerned but I really need to pass the DOMDocument
(or element) as the stylesheet.
    Transformer.transform (sourceDoc, stylesheet, outputDoc);
 
Is anything like this possible? Or do I have to convert my xerces-parsed
DOM tree back to a string and let Xalan re-parse it?
 
Any pointers would be appreciated.
 
Thanx,
   Steve Dussinger