See arc topic, other problem with data connection problems :Thanks FXP!
Usually when I insert my SIM card into the devices with CM, they can automatically detect APN info. However, Ray with CM7.1 cannot detect APN info, even though it has my carrier's APN info is in apns-conf.xml. In addition, Ray cannot save new APN info. Furthermore, I installed APN manager, but it cannot activate data network.
I appreciate your effort, and look forward to the fixed version!
http://forum.xda-developers.com/showpost.php?p=18311534&postcount=1263
But don't flash the firmware for arc !!