vCenter 5.1 / SSO permissions issue

So I have vCenter 5.1 deployed with SSO.  I've successfully linked SSO to my domain but when I log in with a domain user I can't see anythink in the inventory no vcenter, hosts etc - just an empty portal.  I added my domain vCenter_admins group to the SSO __Administrators__ group but while that allows members to logon it doesn't seem to give permissions to view and interact with the inventory.  Any pointers?  I'd imagine I've missed something relatively simple as the documentation on working with SSO is pretty poor.

Thanks,

Justin.