With a bit of hacking, I've been able to keep SOAP::Lite working on a variety of systems over the past few years. I have never gotten XML/RPC to work. YMMV

UPDATE: SOAP::Lite has been updated, it works just peachy with Apache 2.0-2.2, mod_perl 2.0+, and NicTool.

The principle problem with SOAP::Lite is the lack of support for Apache 2. However, by simply reading through the porting notes on the mod_perl web site I was able to make the necessary changes and get it working. It would seem that SOAP::Lite has been abandoned at some point it will be necessary to assume maintenance of the module and get an updated version released.

The XML/RPC code yields errors complaining about extra information in the response. I'm sure some someone with experience using RPC::XML could whip it into shape in a hurry, but it's not at the top of my list.