To support KMS activation for Windows 8 and Windows Server 2012 with a Windows 7 or Windows Server 2008 R2 KMS host a hotfix is required. If you try to set the KMS host key without the hotfix you get the message „Key is not suitable“ for this product. After the installation of the hotfix you can set the new KMS host key.
You can downloaded the hotfix under http://support.microsoft.com/kb/2691586
