Adding and Removing DTD reference in adapter module

I am trying to strip dtd reference (doctype) from an xml documents on its way into XI and add the dtd reference to an xml message on its way out of XI.

I would like to do this with module development. We are using SOAP adapter with no soap envelope for these interfaces.

I dont know java at all.

Does anyone have the actual java code to do this?

Your help will be greatly appreciate and ofcourse rewarded with points.

Regards

Haseeb