[exim] Suffix in transport?

I want to deliver a message to a pipe transport, without the suffix, but
aparently this is not the way to do it. What am I missing?

I get the below in the logs, and I am trying to accomplish this:
Bjorkriset-styrelse-owner : "|/home/sympa/bin/bouncequeue
bjorkriset-styrelse@???

(Yes, they finally agreed to build a few custom routers/transports instead
of using an alias-file, which didn't really work well with virtual domains.

Oct 25 23:54:42 haven exim[22590]: 2006-10-25 23:54:42 1Gcqhj-0005sB-IW =>
bjorkriset-styrelse <bjorkriset-styrelse-owner@???>
R=Sympa_Owner_Bounce T=Sympa_Owner_Bounce_Transport
Oct 25 23:54:42 haven exim[22590]: 2006-10-25 23:54:42 1Gcqhj-0005sB-IW
Completed

==> /var/log/messages <==
Oct 25 23:54:45 haven bounced[20041]: error: no address found in message
from j2@??? for list bjorkriset-styrelse

Sympa_Owner_Bounce_Transport:
        driver = pipe
        command = "/home/sympa/bin/bouncequeue $local_part@$domain"
        return_path_add
        delivery_date_add
        envelope_to_add
        user = sympa
        group = sympa
        current_directory = /home/sympa
        home_directory = /home/sympa

Sympa_Owner_Bounce:
        driver = accept
        domains = +ListDomains
        require_files = /home/sympa/expl/$domain/$local_part
        local_part_suffix = -owner
        user = sympa
        group = sympa
        transport = Sympa_Owner_Bounce_Transport