Spam Filter ACCEPT rule not valid

In my setup, I wish to have a moderated member list,
however, I also wish this list to be able to recieve
email regarding bugs from Launchpad
(http://launchpad.net)

The way that Launchpad sends the bugs out is to use
the users email address reporting the bug in
the "From:" header, but uses special headers to
identify the email as coming from Launchpad

Obviously, I could just accept each email as it comes
in, and add each sender to the approved list, however,
I would rather that Mailman accept emails if their
headers match the Spam Filters (and the spam filter is
set to accept)

At the moment, it matches the spam header, but doesnt
do anything to the message - the default action for
accept is "do nothing here" - which then passes the
message down the chain, to be intercepted by another
part of the code that holds the message.

Changing the pipeline won't make any difference here,
as the way that mailman works with this is that it
doesnt set anything to say "approve this" it just
says "we're not going to do anything with this here" -
changging the pipeline would just catch the "Non
member posting" at a different point.

I'd like the Spam filters when set to Accept to
actually ACCEPT the email, rather than just pass it on
to other Handlers.

I'm trying to hack on this myself, and if I can will
post a patch, but my trials have been fruitless so far