Tried this trick one day on the way home from school. Its not that hard as it looks. Set up like a Heelflip except your front foot should be placed like this: Right in the middle of the board and the part where you drag your on your shoe should be lined up with the outside edge of the board. Now it came to me naturally so it didn't take me long to learn this trick. I just tried to kickflip in that position and I spun the board half way and landed perfect on the under side of the board. After another try I realized that I have to tuck up more because I couldn't spin the board fully. I kept trying for another 5 tries and landed it then I lost my balance and fell. I kept trying to land and eventually did. I found this easier than a Heelflip. Try to tuck up as high as you possibly can and you should be fine. DON'T be afraid of landing on the board. Just because the board spins under and a bit behind you doesn't make it all that harder. Just keep trying. Just remember to tuck up and the landing is easy for me but e-mail me if you have a problem. After you finished dragging your foot tuck up quick because the inside edge is going to nail you if you don't. Keep at it and don't be afraid to land. If you can't spin the board fully you need to jump higher over the board. Then tuck up. Keep trying this trick and you should be fine. I landed this trick 9 tries after I tried for the first time.
Good Luck!