I am a student from Japan but studying in america, and my mom agree to buy me an iPad. i found out that i cant use a 3G ipad in america with 3g if i buy it in japan, so im gonna buy it at a retail store when i go back. but then when i pay for the 3g plan, i know that i could sign up on the ipad, but can it pay with japanese visa? since my mom does not have american credit card, i wanted to know. also, without wi-fi, can you sign up on ipad since my school doesnt have wi-fi and im planning to go back myself and buy it myself. please help me. thank you