If he isn't inclined to be a kicker, my favorite way to say "I need your hoof, NOW" when the horse is being a jerk like it sounds like he is being, is to sharply tap the horse right under the fetlock with the hoof pick (of course, if you have one of those sharp hoof picks, don't do that). Usually the horse will pull the hoof right up and you can grab it. I've found that generally I only have to do that once or twice before the horse decides to skip that whole step and pick up his/her hooves when or before I ask.
I ask first and when I get no response, I demand it.
Good luck! :)