[exim] Exim and procmail

Hello,

I would like to use procmail and exim 4, to filter some mail. My exim
server is just a relay one, mails are for users on an another MX. Here
is what I put in my exim4.conf:

Router configuration
#procmail
procmail:
#  debug_print = "R: procmail for $local_part@$domain"
 driver = accept
 local_part_suffix = +*
 local_part_suffix_optional
 check_local_user
 transport = procmail_pipe
#  require_files = ${local_part}:${home}/.procmailrc: \
#                  +/usr/bin/procmail
 require_files = /etc/procmailrc : \
               +/usr/bin/procmail
 no_verify
 no_expn

Transport configuration

# This transport is used for procmail
procmail_pipe:
driver = pipe
command = "/usr/bin/procmail -d"
return_path_add
delivery_date_add
path = "/bin:/usr/bin:/usr/local/bin"
envelope_to_add
check_string = "From "
escape_string = ">From "
# suffix = ""


But It does'nt work. As if procmail is never called by exim.

What's wrong ? I change router and transport part several times but
nothing goes on.

Regards

Franck