SMS should be setup automatically. You might need to get a new SIM card (free) from AT&T if it's more than 6 months old. I was having problems with dropped calls on my old branded phone. I called 611, they told me I should try a new SIM and they had noted that on my account. I went to an AT&T store and told them about that. They put the new SIM on my account and off I went. The new SIM works in all my AT&T phones. However the dropped call issue is still there, I think it's just their "less than" Verizon network.

Depending on your email account, I tried Yahoo on the debranded, it sets itself up automatically and works great. You can even set the interval it checks for new email. After you enter your yahoo email, a message pops up asking you if you want to download settings, choose yes and it sets up the account on your phone automatically, and it's IMAP! I don't know if you really need the original email client, but if you do, rebrand your phone.