I am attempting to use my 2 year old Curve 8310 (purchased from ATT) with a T Mobile sim card. The phone works but several Blackberry features are missing, including the ability to set up email internet and outlook email accounts. Also, the broadband connection still says "edge" in lowercaps, which I have heard is ATT specific. Can I use this phone on a T Mobil network?? What do I need to do?