I do agree the MfE has a long way to go in many respects. But I have at least gotten it to do two-way calendar sync with our organization's Zimbra 6 server. After I make a calendar change or addition, if I manually resync MfE. This is not just a "send/receive" command but a full manual synchronization of MfE. I would prefer it did this seamlessly and using push without involving Nokia Messaging but at least it does work for me at some level. The Zimbra version we are running is Zimbra 6.0.4_GA_2038.RHEL5_64.