I hate to say this, but the problem could also be partially you. In the first picture your hands are up, WP riders do this to collect their horse up more. He knows that and is collecting behind. In the second picture you have way way way too much contact on the reins, forcing him behind the verticle. WP requires a super loose rein, no contact and very very subtle cues. I believe this horse could do that, if you give him the slack. Would love to see some pics with a slack rein.
Put him in a loose ring french link snaffle, get rid of everything to do with shanks and curbs for now, the leverage is going to put him behind at this point - no matter what. And learn to ride with your seat more, instead of the reins. Really work on just riding him around, nothing special, don't work on his frame/head/neck - go on trails, learn to jump, do something! But get out of the rut you are in.
Good luck, he is a beautiful horse.
Add: These types of bits are meant for neck reining on a loose rein, not split reining.
Last edited by nherridge; 11-01-2011 at 06:43 PM.