When using "SoapServer::setPersistence( SOAP_PERSISTENCE_SESSION )", you apparently MUST include the class that was used in "SoapServer::setClass()" BEFORE any "session_*" commands.
I found this out using "__autoload()" and a whole lot of "syslog()"; it kept failing to include the class that I was using for my soap server, but that class is ONLY ever referenced by the page itself, and even then only for the purposes of setting the class for the soap server; none of my code would ever cause it to autoload. The problem was that I was including my session-handling code first.
If the session gets started BEFORE the page defines the class definition, then persistence CANNOT happen.
The order should be:
1. Include the class for use with the soap server.
2. Start up your session.
3. Set up your soap server.
4. Handle your soap request.
