If you need 3G toggle to use 2G/GPRS/EDGE, you can have it deleting 3 files.
Install iFile. go to Library/Carrier Bundle.bundle and then, delete "overrides _N41_42.plist" and "overrides _N41_42.pri". Then go to Library/Carrier Bundle.bundle/Signature and delete "overrides _N41_42.plist".
Restart your iphone and voilà.
You'll loose 4G Toogle.