TB, when asking the horse to do any groundwork, remind yourself that you are the teacher. Pretend you are attempting to teach a person who doesn't understand English. Sometimes you would have to explain, using your hands to achieve the simplest thing to get them to understand. This foreigner is your horse. Teach him in small increments. To back a horse up, that hasn't a clue, I'll apply pressure to the noseband and tap the shoulder of the most forward hoof as that is the one that will take the step, then immediately remove the pressure on the halter and stop tapping. Then repeat. He may only barely lift a hoof and you must be ok with that. Horses need three or four times to grasp the concept. As soon as he does a complete step release and rub his forehead, maybe even offer a small treat.