There is no need to wait for the email from Stardock for your serial number for TA!
1)Simply open SDC and click the 'Registration Info' button on the lower right hand side.
2)Then click the 'Lookup serial number' button and make sure the email address shown is the one you pre-ordered the beta with.
3)Then go to your email and you should have received a list of serial numbers from Stardock. The TA serial number should be in this email!
4)Simply go back to SDC click the 'registration info' button again and in the games section copy/paste the serial number from the email into the TA section. Register the change and you will be able to d/l and play the new beta.
Hope that helps a few of you
BTW if Stardock have not processed your serial number you will still not receive it in the registration number email!
User made mods for the Galciv II community