Hello,
I believe you have purchased - Symantec Protection Suite Enterprise Edition for Endpoints 4.0, which includes:
In your case, You already have SEP 12.1.671 on Windows 2008 virtual server
and
want to use a virtual Windows server 2012 64bit with 4GB RAM to implement the newer version of SEP which is 12.1.3, correct?
I would suggest you to move the SEPM 12.1.671 to a new VM machine by working on the steps provided in the Article below:
How to move Symantec Endpoint Protection Manager 12.1 from one machine to another
http://www.symantec.com/docs/TECH171767
Once the succesful movement is done to the Latest VM machine, you may follow the Best Practices to upgrade to SEPM 12.1.3001 -
Best practices for upgrading to Symantec Endpoint Protection 12.1.2
http://www.symantec.com/docs/TECH163700
Once, the Migration is done to the Latest SEPM 12.1.2, you may like to check these Best Practices -
Best practices for virtualization with Symantec Endpoint Protection 12.1.2
http://www.symantec.com/docs/TECH197344
Symantec Endpoint Protection 12.1 & Virtualization
http://www.symantec.com/docs/TECH194383
Does Symantec Endpoint Protection 12.1 support VMWare vShield?
http://www.symantec.com/docs/TECH175568
Hope that helps!!