From http://cpansearch.perl.org/src/RJRAY/RPC-XML-0.66/README.apache2:
At present, this package does not work with Apache2 and the soon-to-be mod_perl2. The changes to the API for location handlers are too drastic to try and support both within the same class (I tried, using the compatibility layer). Also, mp2 does not currently provide support for sections, which are the real strength of the Apache::RPC::Server class. As time permits, and the Apache2/mod_perl2 API develops, I intend to have versions of both Apache::RPC::Server and Apache::RPC::Status for that platform.
I am sad. :( Back to working with a RPC::XML::Server server.