It appears that the VC 5.o appliance doesn’t ship with any method of adding a local user via the vSphere client. As my customers deployment only required a couple of local users setting up a NIS or an AD server was pointless. Therefore to add a local user:
1) SSH to vCenter appliance
2) Add a username called username1
# useradd username1
3) Change the password for username1
# passwd username1
4) Login into vCenter as root then right click on the datacenter object and Add Permission. Add the user under Users and Groups and select relevant relevant role.
That should allow the user to log in via the vSphere client. However, the user can not log into Web Client (eg https://10.0.0.1:5480)
I will post the results when I work this one out.