J.C.
I am not there yet with potty training trouble, but one thing i can think of that you can try is positive reinforcement when he does not make an accident in his pants. so that way he begins to associate going to the potty in the toilet and not making a mess with good feelings that he wants to recreate each time. and as he does better and better use verbal rewards "good job", "i'm so proud of you" etc. so that the positive reinforcement continues but you are not crossing the "bribing" line. this may not help at all, but good luck!