Hi,
"Welcome in the world of HP Data Prototector Documentation, which in any case will be inconclusive and very much incomplete.
When you buy this software, you will definitly need to polish up your Trail-and-Error skills since you will need them a lot.
And if it doesn't work as described, or it isn't documented at all in the state-of-the-art cross-referencing PDF documents, just open a support case and maybe you will have your answer in a week or two."
You will need to install a Data Protector client on de vCenter Appliance, which is a SuSE Linux Server.
But since the only proper way to install de GRE Web Plugin (read: fairly documented) is by adding a component to your vCenter server, you will have to setup a complete Linux Installation server.
Unless this is documented otherwise or HP changed the way the plugin is installed on the vCenter server. (which I doubt)
Regards