I've had a few stubborn ones, and they've been the most intelligent ones. Also, once they know their "job" they will work hard to do it!
I would try to make tasks for her. If you want to canter, say, think it out, where you want to go, and where you want to stop, so in your mind it's a complete "thing." Then when she's completed the routine, tell her! (I use treats to start.)
I had a stubborn pony, I had to start with a single lap of a circle, before he started to get the idea that I had "things" for him to do, after which he'd get a bit of carrot, or cookie. It didn't take long before he started looking forward, waiting to see what the "task" was. But at first, don't expect perfection. The general thing you want to teach, is that there's a specific job to do.
Hope this works for you!