How to force Mountain Lion "NetworkAuthorization" prompt I remember being able to make the edit 

defaults write com.apple.NetworkAuthorization ShowAuthUI -bool YES


back in the day, in order to force username/password prompt for users connecting to AFP file servers. I'm experiencing an issue with multiple computers; when trying to connect to a file server on a different domain the user's domain credentials from their current domain are being used, and not the domain credentials needed for that specific file server on the mentioned domain.

That's why I would like a solution like the one above known to work with Mountain Lion, which that one is not.

I've also tried clearing out and removing the keychain, browsing bonjour through Finder (which still allows a "connect as" login box to be pulled up) but the server, being on a seperate domain, is not showing up.

Any known solutions or suggestion? My workaround currently is to "connect to server" using afp://username:password@fileserver.domain.com doing that allows proper authentication to occur and/or pops up the username/password dialog prompt. That is a fine workaround for me, but our hundreds of users would not appreciate the added complexity.
I just found that if you use IP address instead of name of server 10.8 does prompt you for username / password!
Why? I have no idea.