I got my Verizon iPhone 4S SIM unlocked yesterday morning. When I put in my foreign SIM in the tray, the phone roams on AT&T successfully; in the Settings -> Carrier menu, when I take it off Automatic I see AT&T, T-Mobile, and another local GSM carrier. The problem is that I can't switch back to Verizon without taking the foreign SIM out first and reconnecting to iTunes. The Carrier menu doesn't list Verizon as a option when the foreign SIM is in the phone. Is there a way to switch between CDMA and GSM on the phone itself so I can freely switch back and forth between Verizon (CDMA) and my GSM network?