PROBLEMS WITH CORK 7'S

the biggest piss off for me in skiing is having trouble with my cork 7's, i have tried and tried and tried so many times on air bags, on snow, and on tramps and still have trouble with them, it just does not go to my feet, and always goes wanked out, this has been an on going struggle for me for 2 years right now and I feel that this trick is holding me back from my progression, coaches at momentum have tried teaching me this and it just does not work, they tell me to set forward and bring my knees up at 270 and it just doesn't work for me, I have experience with other corks such as cork 5's and cork 3's that I have done on 75 foot jumps and I'm just wondering if anyone has advice or has the similar problem as me, please help!