Black Ops Site Registration

Does anyone know what is the Date of Birth Format when new user register on Black Ops site?

I have a friend who is having trouble with it and I sent emails out to support and have not heard back from them.

He has tried mm/dd/yyyy and mm/dd/yy also dd/mm/yyyy ;  when doing any kind of date format it is always comes back stating "Date of Birth is required".

Any feedback is welcomed.

Thanks