You bought it from the FG store, right? I did a little digging on the forums and found this:
(03-03-2010, 06:14 AM)jens Wrote: You have to send me a pm with some details about what name and email you used when buying the game so that I can dig it up!
It was from a few years back, but hopefully it's still accurate.
Editing my post to include this, too:
(04-05-2011, 04:55 PM)jens Wrote: Check your spam box for the order receipt from Esellerate as well, it also contains the serial etc. So good to save that.