Oh Jocelyn, thank you!
Your videos were quite dark, so I couldn't see if Magik was "thinking" to bend the hindlegs? You would see this thought manifest as a tightening of his abdominal muscles near the flank, or flickers of tension in the haunches. You are so paitent though, and I think that is all you really need. Lots of patience. Here is another video of the school halt taken over the course of six months.
http://www.youtube.com/watch?v=1Mf2bfdCXYcThis video must be "approved" because it was posted on (one of) Bent Branderup's site(s),
http://knighthoodoftheacademicartofridi ... #more-2322I really think your patience will win out.
A necessary component of the bending of the haunches is a relaxation of the topline of the horse. If you can do a slight lateral flexion with Magic as you ask him to lean back, it might help. The bending of the haunches is neither an upward or a downward move of the head, but depending on the horse, slightly upward or downward adjustments may need to be made. If you prefer to do this without headgear, then you can first establish body language cues through the clicker training to communicate to the horse that he should raise or lower his head (or do a little lateral flexion of the poll) so that you might help him to realize the goal of lowering the haunch.
You will work through, patiently, all his guesses of backing up or his desire to step sideways out of the situation (which you already do) ensure he is relaxed and simply aid him to find the answer you want him to find.
So all the focus is on the haunch and the job they must do, with less focus on the head/neck (only for small adjustments) and none at all on the forelegs. The foreleg will do what it will do as the haunches sink lower, OR you can ask for the action of the foreleg directly once the haunches are already bending.
If the horse seems relatively incapable of bending the haunches, then work in hand on lateral movement such as shoulder in, that promote the lowering and bending of the haunch will help with the over all project.
The last point I add, is that in shoulder in, in hand, you are careful that the lateral flexion comes from the poll and not the base of the neck, and that there is a gentle curve/bend through the whole body of the horse. The shoulder in improves through practice, so it too, is a process.