No, you're not required to use the WSDP. There are lots of other
SOAP engines (from Apache, The Mind Electric, IBM, etc.) that do not use the WSDP -- neither does Weblogic, I believe.
The WSDP is just an implementation of the specs -- you no more have to use WSDP to do web services than you have to use the
J2EE reference implementation to do J2EE.
Kyle