Standalone Jetty uses a better session ID scheme. This is probably a problem due to the integration of my DistributableHttpSessionManager.
This is done much better in 3.0.1RC1 and even better in Branch_3_0.
Try upgrading. If that doesn't fix your problem, come back to me and I will send you a new jetty-plugin that should.
Thanks very much, I downloaded 3.0.1 RC1 and it works.