Hi Jeff,
There is no such thing as clearing cache regarding WS. When dealing with an external service, first a Consumer Proxy is created in SE80 based on the WSDL. If the provider changes the service in a way, which results in a new WSDL, the proxy needs to be updated with the new WSDL, ie. regenerate it in SE80 or create a new one.
Steps to regenerate from the new WSDL: SE80 -> Edit mode -> Proxy -> Regenerate. Provide the new wsdl file. It might be necessary to recreate the runtime config in SOAMANAGER as well.
Hope this helps.
Cheers,
Attila