[Exim] Exim 4.14 & Mailman 2.1.2

Hi,

I am trying to configure the transport for mailman using the HOWTO on
the website, however I am hitting a slight problem.

Posts to the lists I have set up work fine, however sending emails to
the 'command' addresses does not work.

Mailman is setup to use the domain lists.mydomain.tld, but exim also accepts
mail for mydomain.tld. When the command emails come in e.g.
my-list-join@??? exim seems to strip off the 'lists' part
and tries to deliver it to my-list-join@???.

How can I modify my transport so that these messages are delivered
correctly?

Snippets from my exim.conf as follows:

#### Mailman Stuff

# Home dir for your Mailman installation -- aka Mailman's prefix
# directory.
MAILMAN_HOME=/home/mailman
MAILMAN_WRAP=MAILMAN_HOME/mail/mailman

# User and group for Mailman, should match your --with-mail-gid
# switch to Mailman's configure script.
MAILMAN_UID=mailman
MAILMAN_GID=mailman

## Mailman Router

mailman_router:
        driver = accept
        require_files = MAILMAN_HOME/lists/$local_part/config.pck
        local_part_suffix_optional
        local_part_suffix = -bounces : -bounces+* : \
                -confirm+* : -join : -leave : \
                -owner : -request : -admin
        transport = mailman_transport
        domains = lists.mydomain.tld

## Mailman Transport

mailman_transport:
        driver = pipe
        command = MAILMAN_WRAP \
                '${if def:local_part_suffix \
                        {${sg{$local_part_suffix}{-(\\w+)(\\+.*)?}{\$1}}}
\
                        {post}}' \
                $local_part
        current_directory = MAILMAN_HOME
        home_directory = MAILMAN_HOME
#       user = MAILMAN_UID
#       group = MAILMAN_GID
        user = mail
        group = mail

### END ###

I should point out that I change the user & group lines in the transport
because mailman was complaining that expected the process to be run as
the mail user.

Thanks,

Seth