Try the layback in reverse first. 🙂 If you are strong enough to pull yourself up, you'll be string enough to layback. I've been using this for awhile and it seems to help.
for x knee:
lay at the bottom of the pole with the pole between your legs
walk your legs yo the up the pole
cross one leg over the other in a figure 4 position
grab the ankle of the crossed over leg
and using your abs lift up like a sit up.
Work on coming up to a pole sit.
Okay once you're strong enough and comfortable enough with that...pull yourself up on the pole, do not climb up high. Pull up to a pole sit and be sure your bottom leg has the foot wrapped around the pole, now grab the ankle of the crossed over leg, keep one hand on the pole, unwrap your foot, slowly lean yourself backwards keeping your hand on the pole for stability, when your arm is extended straight slide it down the pole and slowly lean back more, keep your hand up there until the very last point where it is time to go completely backwards.
Keeping that hand on the ankle is going to increase your grip and keep you from sliding - there will be some slide.
Let yourself build up the courage so don't go back until you feel ready it's okay if as far as you get is the "plank" that's fine. The more you do the plank, the sit and work on leaning back slowly the more courageous you will get, the stronger you will get and the easier the move will eventaully be.
Definitely work this in reverse though - it's a great way to build up your abs a bit.