tracking up

[PSCHOPony@aol.com]

My horse was trained for westen pleasure and now he's going into endurance.
He takes very short strides with his hindlegs, which was suitable in pleasure.
Now he won't track up when I ride him. (put his back feet where his front feet
landed.)  When he's turned loose he will or if I lead him.  If he gets excited
and really hurries I think he does as well.  How can I train him to track up?