I wouldn't suggest lots of backing, since that lets the front end become light making it easy for them to go up. But you have to get the hind end engaged and the weight on the front. So yes doing small circles asiking him to move the hind end around without making him go back or to tight as to make him fall over on top of himself. This is what most trainers would suggest. The only other thing I could offer is to change his diet. You would be suprised what a little diet adjusment could do for a horses attitude towards working. What are you feeding him?