Contacts imported from AD Logging in through User Portal

Contacts imported from AD Logging in through User Portal

How do contacts that are imported through the active directory import tool login through the customer portal?  On the main application login page AD users need to select the domain in the log on to section:



But that option does not exist in the log that is shown in the user portal:

              New to ADManager Plus?

                New to ADSelfService Plus?