SOAP-RPC with attachment how ?

Hi

Any idea what's the best way to send out xml file as attachment to
SOAP-RPC web service ?

I have server running SOAP-RPC service on port 7135 and what I know so
far is that it expects
XML file as attachment when you call that service.

Now since I have never done any of these ruby web service programs I
am bit lost here how I can do this one.

Any help/hints are appreciated.

Thank You