For the record, equitation horses are supposed to have a flat jump that jars the rider as little as possible, in consequence, they often can travel hollow and be what's called a "leg mover" - no movement up through the back.
Exacty the opposite of what you want in an event horses.
I started event prospects EXACTLY the same way I started a hunter or a jumper prospect, it was the way they were finished that was different. If the horse was going to finish as a hunter, I concentrated on developing a perfect rhythm in a 12 foot stride that would carry the horse to his fences, jumping form and the shape of the horse's arc in the air - you want a hunter to loaf down to the base of the fence on very light contact, pat the ground in front while pushing off strongly behiend, and drape over the fence with some "hang time." If a horse was going to finish as a jumper, I'd work on developing 3 - 5 distinct paces at the canter, turns on the haunches and short turns, being able to control the size and shape of the arc (a hunter needs one, a jumper needs many different) and jumping the panel at any angle and at any point (cross-paneling, or choosing to jump the left or right side of the panel at will.) If they're going to finish as an event horse, I'm going to do everything I did for the hunter and jumper, plus hack out and jump natural fences such as ditches, banks, drops and water.