iPad 3G Activation & Roaming Questions

I have an iPad 3G in the U.S. and picked up a Bell Canada SIM card. I tried to sign up for service and the carrier setup does not accept a U.S. State in place of a province.* Can I use a third party carrier prepaid iPad MicroSIM to activate the iPad while roaming?You requires activating a prepaid iPad account with that carrier while changing to a foreign MicroSIM to travel.For example: American