The beta was put up last night in 'patch' format because the IT had left the office for the weekend. When everything is done through StardockCentral activation is less of a sticky issue, but when dealing with individual EXE's it becomes more painful 
I dont know much about the matter, but your Serial Number should work when the game requests an activation code. Check your game directory, make sure a sig.bin file was created, and if all this works but the game dosent activate, then you may have to wait until Monday for a proper exe to be released via SDC (unless someone who knows more can help you guys out)
Sorry I don't have more info to pass along 