appendChild(newFragment) problem

Hi,

I finally managed to get my source code running, but I have a little 
problem which can be seen in the attached image (that shows the 
duplicated elements).

I use something like this:

var targetDocument = gBrowser.contentDocument
var newFragment = processor.transformToFragment(xmldoc, targetDocument);
var _documentElement = targetDocument.documentElement;

// remove HEAD and BODY elements
while (_documentElement.hasChildNodes()) {
   _documentElement.firstChild.localName);
}

_documentElement.appendChild(newFragment);

and that works, except that I end up with two HTML elements, one in 
uppercase, and one in lowercase, so how do I prevent this?

TIA,
Michael