xml_set_element_handler and equivalents

I need to do essentially do what can be found in the "XML Tag Mapping example" (http://www.php.net/manual/en/example.xml-map-tags.php) - transform the names of some XML elements. Normally I'd use XSLT for this kind of thing, but due to environmental considerations I can't. I would prefer to do this in a somewhat OO manner so I can hide this nastiness from the rest of the code. Obviously I can't pass any of my XML handler's to xml_set_element_handler as handlers. Nor can I find a way of encapsulating the "map_array" (at least not without duplicating the map). Any ideas? Is there an equivalent for DOM or SimpleXML or something?