Okay so I updated my i4 the other day to iOS5 and I added in this extra email addres I wanted to use for iMessages. I got my i4S today and after wiping that i4 and giving it to my little sister, I thought i'd be able to add that same email address in again- but it gives me an error saying that this email is already in use for iMessages? Anyway I can unauthorize it from the other device somehow?