This only works some of the time. I own Sins, have downloaded the beta patches, but with the 1.1 patch Impulse no longer recognizes my serial number. I've got the number right, it's in the game's case, I've checked it with Support and tried on two different computers.

I will say that Stardock Support has been good to me and helped me fix numerous problems. But seriously, I'm getting tired of numerous problems.  I think Impulse is the biggest mistake Stardock ever made.  It's sad that such a great company, and definately one who listens to their customers, can take such a wrong turn.