Mac OS X: Change default Name when connecting to server

"Actually, there is a real way to change this username.

For lazy people :

To set the current user's short name:

$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseDefaultName -bool NO
$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseShortName -bool YES

To set a custom name:

$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseDefaultName -bool YES
$ defaults write /Library/Preferences/com.apple.NetworkAuthorization DefaultName ""user""
Replace ""user"" with the desired custom name and enclose it in quotation marks.

To set no name:

$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseDefaultName -bool YES
$ defaults write /Library/Preferences/com.apple.NetworkAuthorization DefaultName """"

To set the current user's long name:

This is only necessary if you have made any of the changes listed above.

$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseDefaultName -bool NO
$ defaults write /Library/Preferences/com.apple.NetworkAuthorization UseShortName -bool NO

or

$ defaults delete /Library/Preferences/com.apple.NetworkAuthorization UseDefaultName
$ defaults delete /Library/Preferences/com.apple.NetworkAuthorization UseShortName"

"Just a guess, but could you create the link to the server with username@servername somehow?

I'm not at a mac right now or I would try."