We bought SSR direct, and we were "in the system" a day after they received our signed paperwork. We don't officially close until July 27th. We didn't receieve any paperwork about our members website login, but when we called MS to book a our Oct 31 cruise, I asked and they furnished the information.
Call MS or your sales guide. The worst they can tell you is that you are not in the system yet.
PS, the website looks nice, but I consider it virtually useless. There is no way to book anything. Only REQUEST - kindof wierd. I expected the website be more dynamic. From what I read on these boards, it will be some time (if at all) that you can reserve rooms, manage points, etc...