How to close a Keel client session/context?

Hi,

I have a "client" model that takes external session based input from a
wireless phone USSD session. It then calls my business-logic model using
JMS. I have not written this "client" as a "clnt-???" yet as I also access
the same business-logic models from a struts client.

I call the Keel model with the request attribute "sessionid" set to my
wireless session id (param.sessionID - a mostly unique number) as follows:

        req.setAttribute("sessionid", "ussd-" + param.sessionID);

I then use a "stateform" to save data across the different business-logic
models in my app as follows:

    DefaultContext context = (DefaultContext) request.getContext();
    try {
      rf = (RegisterForm) context.get("stateform");
    }
    catch (ContextException ex) {
      context.put("stateform", rf = new RegisterForm());
    }

RegisterForm is a bean where I store my data.

All is fine until I come to the end of my wireless session and I need to
release/free the Keel session/context as the wireless sessionid may be
reused at some point (it is only unique for the duration of the wireless
session). I cannot find any place to free up this session in Keel.

I've looked at the other clnt-'s and they either use "default-session" or
a http request session id. I cannot locate the code where these sessions
are released.

Does anyone know where/how to release/close the session in Keel?

Thanks for the help,
Max