On XBOX 360, I recently activated a BF3 Premium account.
Despite this, Battlelog keeps ignoring the fact that I own a Premium account and still shows that I should buy one (laugh):
I bought the Premium package on the XBOX Marketplace, I don't know at this point if this prevents Battlelog from showing it, but I formerly got Back To Karkand still from XBOX Marketplace, and that is recognized, as you can see:
I don't know how to activate it on Battlelog.