How to attach a DOM tree to another?

[Jane Jin \(janej\)]

Hi xerces gurus out there, 
 
I have two DOMDocument* object -- say doc1 and doc2. I'd like to make
doc2 a child of doc1 -- sort of doing:
 
(doc1->getDocumentElement)->appendChild(doc2)
 
Of course I can always parse doc2 into individual DOMNodes, traverse the
doc2 tree and append node one by one to doc1. But is there a quick way
to do this without parsing doc2? 
 
Thanks,
 
Jane