So you’ve got a Windows 2008 R2 domain and a KMS server that services licenses for all your desktops and servers. You’ve also got people itching at the bit to be able to install Windows 8 on their desktops or Server 2012 on their servers. And they also want to be activated. What’s an admin to do?
First off, your KMS server needs to be Windows 2008 R2 SP1.
Then you need to go register, download and install this hotfix on your KMS server: http://support.microsoft.com/kb/2691586/EN-US
That hotfix will require a reboot of course.
After the reboot, go to a command prompt and type: slmgr.vbs /ipk KEY <== Where KEY is your 2012 KMS key from the VLMS site
Once it tells you that the key install was successful type slmbr.vbs /ato to re-activate your server against your new KMS. It should show successful as well.
After that you can type slmgr.vbs /dlv to get a look at your KMS server.
Your description should now show VOLUME_KMS_2012_C channel. And you’re done!
And the client keys are here, in case you need them: http://technet.microsoft.com/en-us/library/jj612867.aspx