I'm sure many will disagree with me, but when I was teaching scuba, I would not let a new diver take a camera on their first trip. Both require skills to do correctly, and it's easy to get distracted while you are taking pictures underwater. As others have said, the number of new divers/photographers that destroy coral and /or sea life is quite high. Add more controls on a underwater camera and it even goes up.
From looking at your portfolio, I don't think you would be happy with a "PHD" (Push Here Dummy) camera , so I recommend that you get as much bottom time as you can before you toss a camera in the mix. I was a pro photographer before I became an scuba instructor, so I know what you are talking about. I'd also suggest that you get a specialty underwater phootography certification.
Can you do it? yea, lots have..but I'd venture to say a very small percentage do it while being in control 100% of the time. Don't be a person that can't see the forest for the trees.
I'd agree. Plans:
The local dive shop has their regular open water course coupled to the National Geographic Open Water Diver certification and the PADI Digital Underwater Photographer certification. A little of all of the above, it includes the classwork, pool work, 4 dives for the PADI cert, then another extra pool dive and two open water dives dedicated to the photography end of it.
Figured that would be a good start.
AmbergrisCaye.com 
