I just set up a vSphere / vCenter 5.1 installation.
I added two older hosts (v5.0) to this installation.
I just noticed that while all VMs have been added to the inventory, none of the templates have.
Is there a reason for this? I can't seem to find anything on the Google or VMWare forums.
Browse to the datastore in which the template is on, find the .vmtx file, right click on it and "add to inventory".