We have made some modifications in SVN revision 8016 about enhanced ICE support and interoperability with Empathy.
Now everything should work fine between SIP Communicator and Empathy except one thing. We have one issue : when Empathy starts a video call to SIP Communicator (videocall from SIP Communicator to Empathy works though). We are in contact with Empathy people and we hope to solve this issue quickly.
Anyway, feel free to test, enjoy Jingle call and send us your feedback.