I just got started with underwater photos too. Although we have aplace in Belize, we went to Grand Cayman last month and the first time we dove, I left my camera on the boat, just to get back in the swing of things. Could easily have taken the camera down the first dive, though. We didn't really have any great current to deal with though, and I suppose that if you are out Turneff way or drift diving it may take more mental focus. Definitely go with the strobe! and arm! Have fun. Belize has so many cool dive sites.
Chris