I've looked for this problem in the forum, and couldn't find one other than from 2011.
Anyway, after updating to IOS 6.1.3 I can no longer connect using the 3G from Verizon. I did read a previous thread dating back to 2010-2011 concerning the same problem with IOS 4. I've tried turning on/off the 3G; turning on/off the ipad. I've left messages with Verizon and haven't had any responses.