Housetraining question. . .?

The reason he won't go outside is because he's being trained to go inside, on the puppy pads. It's very confusing for a dog to be praised for going on the pad and then expected to do the same thing outside. It is better for you in the long run to take the puppy pads away even though he will have messes for a little while. I also recommend adding a word to what he is doing. In the morning take him out AS SOON as he wakes up because he will most likely have to pee, and right after he goes say something like "good potty" and get really excited. If you do this repeatedly you might feel dumb but he will realize that when you say "go potty" or "lets potty" he is expected to do his business.