It seems that the XTags taglib does not support xml-namespaces. Example: 
<xtags:parse> 
  <test><foo:bar xmlns:foo="http://foo.bar">Test</foo:bar></test> 
</xtags:parse> 
<xtag:forEach select="//foo:bar">found</xtags:forEach> 
does not find the element.  
 
The prefix has to be bound to the namespace URI somewhere. I suggest a new tag 
element 
<xtag:bindNamespace prefix="foo" uri="http://foo.bar"/> 
which adds the namespace binding to the context of the xpath expression.