i hear them yeller dogs are born knowing how to stop runners, and load up too! maybe the trick is get a yeller dog....
seriously maybe try to get some cheap weenies and cut them up, start with something low put a couple chunks of weenie on it and tell the dog load up. after it masters that go to something higher until you get it jumping in the truck or dog box. I need to work with a couple of my dogs too. lol good luck