When I try to retrieve voicemails from my iPhone 4, a message pops up telling me that my voicemail password is incorrect. A box appears where you are supposed to type it, but there is only a numeric keypad, there is no way to type letters. Same thing when I go into Settings and try to change the voicemail password; a numeric keypad only, no provision for entering letters. Is this the way its supposed to be? When I was using my old 3G, it never even asked me for a voicemail password.