I had originally intended the module CGI::XMLPost to be a lightweight replacement for CGI where the only stuff being posted was going to be XML and for the received XML to be processed however the receiving application saw fit. But being bored I thought that it really wouldn't be that much trouble to add an as_xpath() method to it which would do what you want :-) So if you download the 1.3 version of CGI::XMLPost it should suit your purposes.

/J\