Installing and upgrading the VMware vCenter Server Appliance in vSphere 6.0 is significantly different than previous releases. The install and upgrade processes for vCenter Server Appliance does not make use of any features related to OVF import in our various clients.
in this way you can mount the iso file to your CD and install or upgrade
You might think that the new vCenter Appliance (VCSA) 6.0 is only being distributed as an .ISO. While I do wish an OVA/OVF would have been available too, the new installer is pretty sweet.
Go to this folder VCSA
you will find a file with no extension you can extract all .iso file content to another folder
you find the appliance virtual machine