Win2008 R2 Server with KMS not accepting Win7 key

We have a new Win2008 R2 domain controller wherever we're employing KMS but I am acquiring trouble including the KMS for Windows seven. I activated this server making use of the MAK and after that used slmgr.vbs /ipk to install KMS keys. I was effective in incorporating keys for Win2008 R2 Enterprise and Win2008 Ent. I had difficulty with incorporating the Workplace 2010 key but found this article,Buy Office Standard 2007


which solved that difficulty. Right after installing this I successfully extra my Office 2010 KMS important.

I'm nevertheless not in a position to include the Windows 7 KMS crucial. When I do I get this error:

C:\Users\administrator.CGDEV>cscript C:\windows\system32\slmgr.vbs /ipk xxxxx-xxxxx-xxxxx-xxxxx-xxxxx (KMS essential)
Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.

On a computer running Microsoft Windows non-core edition,Vista & Win7 Self Diagnostics (for normal users),Windows Seven, run 'slui.exe 0x2a 0xC
004F015' to display the error text.
Error: 0xC004F015

How do we use this KMS server to host Windows 7 keys?