Index: library/Zend/Dom/Query.php
===================================================================
--- library/Zend/Dom/Query.php	(revision 24554)
+++ library/Zend/Dom/Query.php	(working copy)
@@ -124,6 +124,10 @@
         }
         // breaking XML declaration to make syntax highlighting work
         if ('<' . '?xml' == substr(trim($document), 0, 5)) {
+            if (preg_match('/\?'.'>\s+<html[^>]*xmlns="([^"]+)"[^>]*>/i', $document, $matches)) {
+                $this->_xpathNamespaces[] = $matches[1];
+                return $this->setDocumentXhtml($document, $encoding);
+            }
             return $this->setDocumentXml($document, $encoding);
         }
         if (strstr($document, 'DTD XHTML')) {