Signing outgoing mailman mail with DKIM

[Zbigniew Szalbot]

Hello,

I used to have a working setup where all outgoing mail, including 
mailman, was being signed. However, I decided to stop using maia for 
content scanning (most of my mail is variuos subscriptions sent to 
outside users) and just sign the outgoing mail with DKIM.

So I changed the entry in main.cf to say this:
smtpd_milters = inet:127.0.0.1:4445
non_smtpd_milters = inet:127.0.0.1:4445

This does what I want as DKIM-filter is listening on port 4445 and is 
indeed singing outgoing mail. However, I am not sure why, mailman lists 
emails are no longer being signed.

Here is the entry in mailman that I have been using all the time.

mailman   unix  -       n       n       -       -       pipe
  flags=FR user=mailman:mailman 
argv=/usr/local/mailman/postfix-to-mailman.py
  ${nexthop} ${user}
  -o milter_macro_daemon_name=ORIGINATING
  -o smtpd_milters=inet:127.0.0.1:4445

And it has always worked well but not anymore. I mean the outgoing mail 
is not being signed. Is there any apparent flaw in my setup? I guess 
there is but I would appreciate if you could give me some pointers.

I am using postfix-2.5.6,1 on a FreeBSD 7.2 system.

Thank you very much in advance!

Zbigniew Szalbot