[Exim] Away Replies and .dbm files

My director looks like this:
useraway:
driver = forwardfile
owners = nobody
file = /usr3/exim/away/${local_part}.away
require_files = /usr3/exim/away/${local_part}.away
no_verify
no_expn
check_ancestor
filter
file_transport = address_file
pipe_transport = address_pipe
reply_transport = address_reply
match_directory = !^/nonexistent
My filter looks like this:
# Exim filter
if personal then
mail
to $reply_address
subject "Re: $h_subject"
text "I will be out of the office from November 21, 2001 until
November 26, 2001\n"
once ${local_part}.dbm
endif
This creates a jkezar.dbm file and stores all attempts to email jkezar.
This file is chown'd "jkezar" and chgrp'd "mis".
That is my uid and primary group id. This all works fine. Except I want
it to be chown'd "nobody" and chgrp'd "nobody"
so that my web interface can interact with this file and delete it when
theuser returns.
Currently the users jkezar.away file is set up with these ownerships. I
have a web interface create the filter files and when they are used exim
created the .dbm files.
Exim created the .dbm files as user jkezar. I want it to create the
.dbm files as user: nobody
Can someone help?
--
Joseph Kezar