This is my situation as well and I blindly went ahead and got the EU version too, POL IDs are locked to their purchase regions and SE will not change them. Thus you have to find some way of getting the expansion and reg code from a friend in the US if you need the US version and a friend from the EU if you need the EU version. Sad i know, SE could really make these reg codes just work universal with only the main game install being regionally locked.