return node-set to stylesheet via php:function

using: RedHat ; PHP 5.1.2 ; libxml 2.6.22 How do I return a node-set to an xsl stylesheet via php:function? I've had no difficulty returning strings, but so far xsl refuses to see the result as something I can iterate as real XML. php fragment: ----------------------------- // return String function getNodesOne() { return '<RESULT><NODE>foo</NODE><NODE>bar</NODE></RESULT>'; } // return DomDocument function getNodesTwo() { $xml = '<RESULT><NODE>foo</NODE><NODE>bar</NODE></RESULT>'; $doc = DomDocument::loadXML($xml); return $doc; } ----------------------------- xsl fragment: ----------------------------- <xsl:variable name="nodes"> <xsl:copy-of select="php:function('getNodes')" /> </xsl:variable> cnt=<xsl:value-of select="count($nodes/RESULT/NODE)" /> ----------------------------- expected result: cnt=2 actual result: cnt=0 Same result calling php:function('getNodesOne') or php:function('getNodesTwo'). In both case, the xsl variable $nodes contains a string, not an actual node-set that can be iterated and otherwise worked with. $nodes/RESULT, like $nodes/RESULT/NODE, doesn't exist. I also tried this, but it returns an empty node-set and not even a string: ----------------------------- <xsl:copy-of select="document(php:function('getNodes'))" /> ----------------------------- Finally, I've also tried this, but libxml2 evidently does not support the inline-data URI form: ----------------------------- <xsl:variable name="tmp"> <xsl:value-of select="php:function('getNodes')" /> </xsl:variable> <xsl:variable name="nodes"> <xsl:copy-of select="document(concat('data:text/xml,',$tmp))" /> </xsl:variable> ----------------------------- So, in all cases/combos of the above code, I get a string or an empty node-set. Clearly, there should be a way to get a node-set via php:function, without creating a temporary xml file and without making a full request to apache. Am I missing something? Is something broken or, worse, broken by design? Any help would be greatly appreciated. thanks