When using a Volume Activation Management Tool ( VAMT ) 3.0 you want to add your Windows 8.1 and Windows server 2012 R2 license keys, to the product keys.
This is NOT possible !!!
Your unable to add the Windows 8.1 and Windows server 2012 R2 product
Read more... Windows 8.1 /2012 R2: How to add new product keys to your KMS server / Upgrade your VAMT 3.0.