I find that draft breeds figure out pretty quick that they are bigger and can avoid having their feet handled by "wiggling" as I call it. LOL If he's not spooky and accepts handling well, I doubt he's having a fear /"prey animal" response. It's more like "I don't wanna". I disagree with the theory that trying to fight the pawing is the wrong thing. I giving up too soon is more likely the problem.
Seriously, the best advice I noticed on here so far was use of ropes. NOT to tie the horse down and break his spirit, but to keep you out of harm's way and to make it a lot easier on your back! Plus, any horse should learn to remain calm at the feel of a rope or something on his legs.Yes, you want to desensitize him to the rope and you can use a whip to touch him first without getting tangled up (not for hitting) although, if he's aiming kicks at you, I'd pop his little ankles for each kick-its completely not acceptable !!! If he's just kicking out, just stick with trying to touch them.
Getting a farrier or trainer that has experience in handling the big guys will help, but warn him that it's an untrained one you have trouble with. He/she can (for a fee) proabably get you started and you take over the daily handling/reinforcement.
I've worked on a handful of drafts..I'm not an expert on handling them, but I have been able to trim them successfully and safely for all involved. But it did take cooperation from the owners, and time. I don't think you can be too firm with these guys, they are too big to take chances, and I've not had any act like they resented me for making them stand still, or resisting their pawing or whipping kicking legs.... Like rebellious kids that respect a firm teacher. But I digress....
With such a large animal (but really, even with light breeds) careful use of ropes are a huge help and keep you safe. Please, get help and soon. Team effort is best in this case, at least at first.