I've been going through this with my current project horse. What seemed to have some success for me was tying him and as soon as he started to paw, I untied him and backed him. tied him, and when he pawed I lunged him. Tied him, then backed him. It was a pain in the neck but he is not nearly as bad now.
I don't think you can fix it. It's a bid for attention, I believe. Ignoring him is better than a reprimand. But having to work seemed to help also.
You can search for my post a month or so ago for other ideas. Several people responded.