Hey Tony - I have Scott Michael's Marine Fishes. According to him, they can be housed in a reef tank. May nip at sponges, tunicates and ornamental crustaceans and snails - but harmless to corals.
I read on Wetwebmedia that this species of trigger can go either way, sometimes they are aggresive, more often they are fairly mellow. They suggest not letting them get to hungry. I was worried about my little peppermint shrimp, but if you add them first (the shrimp) it can work out. So far so good, it has been about 5 days now. Shrimp comes out at night, but that was the only time I saw him out before the Trigger.
My LFS said he would give me store credit, so I can bring him back if it doesn't work out.