I got my CE code this morning (purchased from the SE store) and it took me a while to get it registered. First, it said the code from Digital river was invalid, then the code I got from SE was for the wrong region. Finally went to the Mog Station and entered my code from Digital River there, and it worked! So I finally have my stuff and subscription....

Definitely was a lot of confusion with this because the codes weren't working with SE sites, but there doesn't seem to be anything that points you in the direction of entering the code through the Mog Station. I just figured it out on my own trying my codes every which way. Luck.