I bought two iPod touches (2g) for my two daughters, who each have their own computer. I tried to make the second touch (on second computer) use the same account for the app store, but it won't sync on the second touch because it says I'm on the wrong computer. How do I fix this? Do I have to restore and set up a second account from scratch? I'd prefer to have both kids using the same account using my same credit card.