20 days and you haven't found an answer a 20 second google search would result?
You need to jailbreak. I added Sinfuliphone repo in Cydia and got a cracked version of tether me. That way you can access data settings on your phone. Then go from there. My mms and 3G data has been working fine with my settings long before your original post. Google it don't sit and wait for it to be handed to you