Hey Fred,
Thanks for your information, that helps. Which WP OS are you using that's giving you the MMS and Internet Sharing problems, is it WP8 or WP8.1 Developer Preview? I would totally love to use this phone on At&t's network too, but if there's isn't a fix for MMS then I might reconsider. I can careless with Internet Sharing since I don't use that. Thanks!
Thanks for the response Fred. Do you know if XDA Dev have a code to unlock it by any chance? Also, do you know if installing WP8.1 Developer Preview will make MMS work for the ATIV SE?