[EXIM] Passing local suffix to procmail?

I've recently started playing around with some procmail filters that
require the use of $local_part_suffix; I thought I had this working under
exim 2.x, but I upgraded to 3.0 a few weeks ago and haven't played with
this feature for some time.

This is what's currently in my exim configuration file:

The transport:

  procmail_pipe:
    driver = pipe
    envelope_to_add
    command = /usr/bin/procmail -p -t -a ${substr_1:${local_part_suffix}} -d ${local_part}

The director:

  procmail:
    driver = localuser
    suffix=.*
    suffix_optional
    require_files = ${local_part}:${home}/.procmailrc
    transport = procmail_pipe

The problem: mail address to lars.foo@??? gets delivered to me,
so exim *is* recognizing the suffix, but the call to procmail looks like
this:

/usr/bin/procmail -p -t -a -d lars

(That is, the value of local_part_suffix appears to be null).

Any idea what I'm doing wrong?

Thanks,

-- Lars

--
Lars Kellogg-Stedman <lars@???>


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