[qmailtoaster] SMTP Gateway with Authentication

[mailing]

I would like to ask from the list on how to implement smtp authentication. I 
have tried smtp authentication qmailtoaster box to small businessesand it works 
perfectly. However my solution for an ISP is below.


clients/users---->SMTP Gateway------>WWW
client/users<------POP3<------------------<WWW


I would like to implement authentication at SMTP Gateway , but how can I do it 
if the user database is in the POP server.

Thanks,
Manny