[Exim] headers_add & directors

Hi,

I have a director for some sort of mailinglists like this:

list_director:
headers_add = "Precedence: bulk"
driver = forwardfile
file = /etc/exim/virtual/${domain}/lists/${local_part}
no_check_local_user
forbid_pipe
forbid_file
errors_to = su@???

(btw: many thanks to David Woodhouse, your example helped me a lot)

Now I want that users who are on vacation don't generate a vacation autoreply
when they receive the email via the above list. My vacation director looks
like this:

vacation_director:
  driver = localuser
  require_files = /opt/vacation/away/${local_part}
  senders = " ! ^.*-request@.*:\
              ! ^owner-.*@.*:\
              ! ^postmaster@.*:\
              ! ^listmaster@.*:\
              ! ^mailer-daemon@.*:\
              ! ^nobody@.*:\
              ! ^root@.*"
  condition = "${if or {{match {$h_precedence:} {(?i)junk|bulk|list}} {eq
{$sender_address} {}}} {no} {yes}}"
  transport = vacation_transport
  unseen
  user = root
  no_expn
  no_verify

Unfortunately the vacation director does not recognize the precedence header
added by the list director.

In the archives
(http://www.exim.org/pipermail/exim-users/Week-of-Mon-20000515/018219.html) I
found the statement that it's not possible to do filtering bases on headers
added by a previous director. Only headers which have been in the original
email.

Is this still true (exim 3.34)? If so, is there any other way how I can "tag"
a message going through the list director to filter it in the vacation
director?

Many thanks in advance,

Stephan
--
I intend to live forever. So far so good.