Does anyone know if both items need to be purchased at the same time(ie. Same reciept) to qulify for the Double Rebate? Or can I purchase items from two differant stores and get the double rebate? I was going to order a camera from B&H because thier price is so much lower than here in town, but purchase a 580 EX from a local camera shop where I have $200 in gift Certicates to use. Thx.