My mini jumps 2'6. Train her like you would any other horse, don't push them because they will do what you want them to do.
The best way is to ground drive them. Grab a lunge line and start off from scratch. Teach him everything as tho you are going to get on turning, decreasing and increasing paces etc.
I swear I'm the mini jumping guru. I had my pony down to cantering by voice command :)