It is about the same of the LH Member gets Member promotion, and it is possible to get retrospective credit as long as the member is new - you phone them up and ask where your 5,000 miles are, then you say you called them before you registered and they said you could register on-line and they would credit you the 5,000 miles retrospectively
http://www.flyertalk.com/forum/wink.gif
The only problem is I am not sure when the qualifying period ends (or ended).
Circle is the top-tier in Qualiflyer, after TravelClub.
Nick