I had the same problem. I'm using the same sliders in my MD/texas tech dynasty. You should try going in to practice mode(make sure it's on heisman), place the ball at the 35 or 40 yard line, and just kick until you get the hang of it.
I put the ball on the 40(which i believe is a 57 yard kick) and didn't stop until i made one.(btw, i was using md's freshman kicker). It may be frustrating, but it'll help you get the timing down.