XPP Web Services

Can someone tell me about XPP Web Services and how I can learn more about them? What interfaces/protocols does it support?  I assume it supports SOAP, but does it also support REST?  What kind of server does it run on (ex., Tomcat)?  Any other information about how easy or difficult it is to setup, stability, etc., would be helpful.  Also, I looked for documentation but couldn't find any. 

Thanks.