This is now available from the following link:
http://downloads.qbik.com/qbiknz2/downloads/Mail_Server_6_Scenarios_and_Configurations.pdf
This is an updated and expanded version of the previous WinGate Mail Server document, and deals exclusively with WinGate 6 Mail. It includes everything from basic email concepts, to a comprehensive overview of WinGate 6 Mail's feature set, through to advanced network configurations into which WinGate 6 Mail Server can be integrated.
Regards
Neil