After the Vista Credential Provider (GINA) is installed there are multiple User Logon Icons displayed:
The standard Windows Vista User Icon and the Vista Credential Provider Icon (both for the same User).
How can you setup/configure the Vista Credential Provider to only show one User Icon (CA Vista Credential Provider Icon)?
In the CA Credential Provider Configuration utility (CAIMCredProvConfig.exe), there is a checkbox for "Disable Microsoft Password Credential Provider".
Checking this option and rebooting the Vista machine will disable the default MS credential provider and you should only see CA Icons on the logon/unlock screen.
This is assuming no other 3rd party credential providers are installed.