For F/T I have tried 2 methods so far. First I take the rat out of the baggie and put it on the top of his cage to thaw. Once thawed I will either heat up some water(i have tried wet and dry rodent), or get the blow dryer. I heat up the prey to about 90 deg, and then I open the tank and try to find him. Usually I can find his nose poking out of the substrate, so I try to tease him with it. I spend about 15-30 minutes trying to get his attention while he is in the substrate. Now if after 30 or 45 minutes I am unable to get a response, I will then pull him out of the substrate and try again. If that doesn't work I take a paper towel, and put the prey on it and leave it overnight. I try to heat the prey back up about every 5 - 10 minutes, until I put it on the paper towel.
When I do live he eats within 5 minutes of being presented with the prey item.
Do you think you might be scaring him? Have you tried just placing inside and leaving it and have the room dark and quiet?