Where to add Win Server 2012 Datacenter Key in VMware

Hi All,

We have 1 ESXi 5 server with 2 CPU's, we have purchased Windows Server 2012 data center edition 2CPU license. As per the page no 7 of below article in you can use Windows Server 2012 data center edition in VMware environment and with one data center  license you can install unlimited VM's under it.

https://www.google.ae/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fdownload.microsoft.com%2Fd…

My question is we have MAK key for Windows server 2012 DataCenter & we would like to create different Virtual machines with different editions of OS like Win Server 2012 Stnd, Win Server 2008 Std etc. But when we try to put the same Win 2012 Datacenter edition key in standard edtion it does not work. How to use the key for activating Virtual machines.

Second question is if i can create unlimited VM's with 1 Windows server 2012 data center edition than how Microsoft will control is someone use same key at different environment like with different ESX server because each VM is a separate entity and keys are entered in guest OS not on the vCenter level.

Please advise as i cant find any relevant answer yet.

Regards,

Khurram Shahzad