Is there a way to force IIS to accept domain credentials without requiring the user to enter the domain name at the login prompt?

Our config so far:
- We removed anonymous user access from the affected website folder, and added domain accounts/groups to the directory permissions.
- In the IIS Manager, enabled "Digest authentication for Windows domain servers", and entered our domain in Realms for the affected folder.

In Firefox we can authenticate with just a login/password, but in IE we are still forced to provide the domain.