I'm probably only a few days ahead of you in progression so I know exactly what you are feeling. I think the problem is that the more you hit the knuckle the scarier it gets, since your mind is learning to expect pain every time you get close to the lip. You're essentially training your body to fear the jump more each time you hit the knuckle.
As others have said, your best bet is to learn to bomb groomers and get your body used to high speeds, and hit smaller side hits as well. It will feel absolutely amazing the first time you land on the sweet spot since it's such a smooth feeling (provided your board is relatively flat on takeoff and your body is aligned properly). After that you almost begin to realize that the more speed you carry the easier the jump will seem.
As someone else alluded to, it's easier to progress if you spend more than one day on the same jump...sometimes what your mind needs is sleep to really get used to all the movements, it will all seem easier on the second day. I was riding last week and spent most of my day on one park run that had three jumps, two 10 footers and a 15. I must have done the run at least 12 times so we're talking over 30 jumps in one day, but even till the last hit I felt an insane rush of adrenaline every time I landed (80% of those were clean mind you) and I definitely feel that I would get rid of the fear if I could have been up there for another day.
You've already conquered the most mentally difficult part by brining yourself to hit the lip in the first place, so you're almost there!
Last edited by doron; 01-14-2011 at 02:00 PM.