I also am having dificulty finding where to enter Registration Codes. I reactivated accounts for my wife and I and need to enter codes for expansion packs that were released after we stopped playing a couple of years ago. I have searched all over SE account management site and have yet to find where I can enter them. It is very frustrating since we both use XBOX 360s. I even installed the game on my PC and still I get redirected to SE account management. I hope they fix this issue soon.