Definitely make sure it's warm enough!! I always thaw and heat up my rats in warm water, and then right before I offer them to my bp, I use a hair dryer on them for a couple minutes, mainly around the head and upper body. That and doing the zombie dance works like a charm for me. Some bps like to be more difficult though.

And I second what Kymberli said... the most important thing is to make sure he's eating and at a good weight before you try to make the switch. So if he's used to eating live, feed him live the first couple of meals and see how it goes.

Good luck!!