SQL Server 2012 evaluation can be activated by "upgrading edition" in the SQL Installation Center. You punch in the product key and you are done.
Problem1: is if you purchase the license through the VLC, then the keys are not displayed. They're embedded into the installation media available for download from VLSC portal.
Fix1: Read a couple of blogs like this: http://www.nogeekleftbehind.com/2014/05/28/upgrading-sql-evaluation-to-volume-license/and followed the steps to "extract" the embedded VLK from the installer.
Problem2: Error message "the key is not valid" when trying to apply extracted VLKin SQL Server trial.
Fix2: (a) find a way to get the key applied since it looks like it works for others like a charm, or (b) uninstall the trial and install the VL one.
Need help with both (a) and (b). If (b) is inevitable, then how to...