Yeah, it is really hard. First of all, practice the parts you're having trouble with slowly and daily. Also try to daily practice it to a metronome and maybe the whole thing as far as you can up to speed.
Also watch Papa Gates lessons on tapping and try those exercises too. I believe he has some on two finger tapping as well. Lastly have a look at Syns Tapping Etudes and try them. You don't need to get them to 100% speed but the exercise will get your fingers in shape. Good luck. Make sure to share your progress with us!