be careful about the receipt tho, make sure it says both the day of purchase and the amount you spent/form of payment! the first time I did it I attached an invoice that didnt have the price I paid for the shoes, and nike sent my shoes back saying they can't process it. I learned my lesson and make sure I have everything before I send them out. I actually just got a confirmation email today from nike saying my AO12 CB4.3's I bought from TW when they were on sale have been approved! about time too, as I'm low on vouchers
good luck!