Getting rid of the att no internet share message is easy if you have interop unlock. You will need to send root tools to the phone with a xap deployment tool (like from the windows phone sdk) then use the registry editor to add this value
Then edit this value so it reads:
Here's a link to a thread that explains the process poorly. The key is to have the two lines above in your registry. No matter how you get to the regediting step. Worked for my focus flash.