Do you have sysprep installed on the Virtual Center? Check the link below to confirm version and location:
You should not have to Sysprep your template first. If you save the template and run the "Customize OS" in the VG Job it will call on this file in the VC to perform the SID changes.
We're using Server 2008, so as far as we know and the link confirms this we don't have to have it installed on the vc.
I was under the same impression that we shouldn't need to sysprep first and just choose customize os but when we do this we still get the same SID for the server.