For other users looking for activation options for Windows Server 2012 using Windows Powershell you can use the slmgr.vbs /ato command to attempt online activation this also works with the command prompt and with the "Run" Command.
The slmgr.vbs and slui.exe commands are the Same for Windows Server 2012 and Windows 8
These can be typed at the command prompt, in the Run box, or by searching for the application in the start menu.
slui.exe 4 Phone activation
slui.exe 3 Product key Entry 5x5 (XXXXX.XXXXXX.XXXXXX.XXXXX)
slui.exe Displays current Activation status
Corresponding slmgr commands
These can be run in Powershell, The command Prompt, or in the "Run" Box
slmgr.vbs /ipk (Insert product key here) allows Entry of the correct product key if not entered during installation
slmgr.vbs /dlv Displays all current software licensing information.
slmgr.vbs /ato Prompts Windows to Attempt online activation
If you type slmgr.vbs without the corresponding /action it will list all available actions for reference. It will also list the commands if you mistype one.
Microsft TechNet slmgr.vbs Reference
Edited by Sneakycyber, 08 April 2013 - 08:59 PM.