dear thomas_chan,
Charlie Brady developed a contrib to do what you want. We use it and it works perfectly on 5.6. Have not tested on 6.0 but plan to soon. Below is how you set it up.
1) From your closest mirror, download the rpm. Example:
http://mirror.aarnet.edu.au/pub/e-smith/contrib/CharlieBrady/RPMS/i386/mailfront-0.91-8es.i386.rpm2) Use the server-manager to add a user named 'maillog'
3) Add the rpm:
# rpm -Uvh mailfront-0.91-8es.i386.rpm
4) Add the environment variable:
# echo maillog > /var/service/smtpfront-qmail/env/LOG_RECIPIENT
5) Send some e-mails and you should find messages delivered to intended
recipients plus archival copies in the 'maillog' inbox.
Good luck.
Does anyone can advise how to capture all outgoing mails at QMAIL server so that to allow the management to review all the outgoing mail details ?