I prefer to do this one with a 1/2 spin first, then move into the back hook. It was easier than just doing the pivot for me. Also, it will give you more momentum than just pivoting into it as well.
If my R hand is on the pole, I will swing my left leg around to try and touch my right toe (on opposite side of pole.) Once the left foot touches floor, begin the pivot, throwing the right leg to the side, and behind. Only after the pole comes in contact with left knee pit, can you bend Right leg, throw your hips forward, and head back into that open hook position. I don't know if that will help at all, but try to wait for the pole to hit your knee, and not lift knee onto pole early on.
Once you get good at it, you can lift yourself up onto pole for longer spin, but I don't recommend that starting out :-)