I had written a SOAP::Lite client/server application. SOAP::Lite side was not so bad as long you did not use its custom serializer with custom XML docs.

The thing about SOAP is that it just encapsulates a message, a request for a service. What that request should look like and how complicated your SOAP server depends entirely upon you. I don't think that Perl is any worse than any other language. As far as data sharing of XML documents, Java had some exceptional tools but they may or may not be what you are looking for.