Hi Nitin,
if third party is able to generate the XML then should have XSd you can ask the XSD and use the same no need of DT/MT.
Alternative using XML you can generate XSD and use it in mapping but you need to be careful about the fields which are not present in the current XML and also the occurrence of the nodes.
I gave a try using XML anonymizer bean but still the attribute remains after applying this module.
like : <OP dt="i4">2</Op>
Br,
Manoj