I have a BB 9000 and its connected to a BES service at work. When I make a change on the berry in calendar (not sure about contacts since havent tried it), it immediately erases the change since I guess it keeps whats on the desktop. If I change on the desktop, then its fine.
I dont see an option where the most recently edited entry should "win" any sync.
contacts work fine and I can successfully add a new calendar appt to the handheld and it will sync OTA with the desktop.
The problem is just with editing existing calendar appointments on the handheld. Any changes made to an appointment revert back to what is on the desktop.