Hey guys
This is working as of 1/16/12
What you need is to have an account ready to prestige, and a friend to help you with the glitch.
How to do the glitch:
1. Go to the custom class that you want to keep when you prestige
2. Go to copy and hover over class 1, or whatever you prefer.
3. Get your friend to go to private match/find match with you then immediately back out.
4. You should be able to still see the copy class menu, but not use it.
5. You should be able to scroll in the background.
6. Go to barracks and prestige.
7. Now click A on the copy class slot ( if you still can't scroll, press "B")
8. Now you are done.
9. Have FUN!