Minutes.
However, if it does not do that for you, there are steps you can take to fix that.
1) Clean out any items still waiting in your download list
2) Remove your username and password from options
3) Close the game. Wait till TADDeamon has stopped (can take a few minutes)
4) Restart the game
5) Re-enter your username and password
That should do it. But before doing this, check if you indeed activated the FCT (and not just buy it).