Gevey Sim Not Working with iPhone !! PLease Help!!!?

I installed iOS 5 beta 3 on my iPhone 4 but when i try to use Gevey Sim with my iPhone everything works well and i get my carriers's name also on the top left but There are no signal Bars! and my Phone is not able to make or receive phone calls! Please Help ! If Possible please tell me all the exact steps to unlock ios 5 beta 3 with gevey Sim and also please tell me if there is a problem which i am facing and a fix to it ! Thank You In Advance! and My iPhone 4 has a baseband 4.10.1 and it is officially activated by At&t sim ! if that helps! Thank You!