Hi,i am aware of the fact that if one doesn't want to open an itunes account in the very beginning,one can simply open an apple app store account and download free apps from apple app store,but what i don't know is that if one ever changes his mind and decides to make an itunes account to buy chargable apps,games and music can he make an itunes account with his existing apple app store id and just provide his credit card details?Please reply.