// Query from the node, according the the select pattern in the
// use attribute in xsl:key.
XObject xuse = kd.m_use.execute(execContext, testNode, nscontext);
NodeList nl = xuse.nodeset();
if(0 == nl.getLength())
continue;
// Use each node in the node list as a key value that we'll be
// able to use to look up the given node.