Yes, I realize that this is a little bit late as the August Preview build expires today, and may have already expired for some of you, but hopefully you can gain access to your server long enough to perform the following steps to extend the timebomb to mid-March.
1. Install WS08 R2 SP1 RC on the server by clicking here
2. Logon on https://connect.microsoft.com/WindowsHomeServer with your connect credentials
3. Click on Product keys (in the left hand side column)
4. Click on Request a new product key
5. Click on Get Key
6. In Windows Home Server, open a command prompt
7. Type “slmgr.vbs -ipk ABCDE-FGHIJ-KLMNO-PQRST-UVWXY” (where ABCDE.. is your new key as requested above)
8. Type “slmgr.vbs –ato”
9. Reboot the server, and your beta timeframe has been extended. You can check this by opening up a command prompt and typing winver.