Using qmail to archive outbound and inbound mail

[Phil <philsross@gmail.com>]

Hi everyone,

I'm transferring the responsibilities of back-end mail server,
interface, and spam filtering to Google Apps.  However, I still want
to use my qmail server as a gateway to archive users mail for legal
and compliance reasons.  Google will allow all outgoing mail for our
domain to go via a smarthost, and to use qmail to archive this mail on
the way through, I could only find Inter7's qmailtap patch...

To archive inbound mail, I have provisioned the Google side of things
as "staff.mydomain.com" with the appropriate MX, but the MX to
"mydomain.com" will still go to my own mail server, which currently
uses fastforward aliases to forward to "user@staff.mydomain.com" at
Google.

However for inbound mail I would like to save a copy of the email in
the users .maildir, before forwarding it on to the Google mail
servers.  So I'm guessing a .qmail file in the user's directory with
both a forward to "user@staff.mydomain.com" *and* a local delivery as
well.

The inbound mail will end up at Google, with a copy saved in the users
directory that I can retain for a period and then expire with some
tool.

Does this sound like a reasonable approach to the problem, or am I
overlooking something?  Any advice would be appreciated.

Regards
Phil