[exim] question about exim and couriser imap setting

Hi,

I am using Exim 3.36 under Debain Linux Woody. Now I try to setup
Courier IMAP with Exim. I use the config example from
http://www.trekweb.com/~jasonb/articles/exim_maildir_imap.html. It
works fine for me. The only problem I got is that I try to keep one of
my user still using POP3, not IMAP. Here is my Exim.conf

######################################################################
#                      TRANSPORTS CONFIGURATION                      #
######################################################################
local_delivery:
  driver = appendfile
  group = mail
  mode = 0660
  mode_fail_narrower = false
  envelope_to_add = true
  return_path_add = true
  #file = /var/mail/${local_part}

# IMAP
directory=${home}/Maildir
maildir_format = true
prefix = ""

......

address_directory:
driver = appendfile
no_from_hack
prefix = ""
suffix = ""
maildir_format

...... Skip

######################################################################
#                      DIRECTORS CONFIGURATION                       #
#             Specifies how local addresses are handled              #
######################################################################

real_local:
prefix = real-
driver = localuser
transport = local_delivery

userforward:
driver = forwardfile
file_transport = address_file
pipe_transport = address_pipe
reply_transport = address_reply

#IMAP
directory_transport = address_directory

no_verify
check_ancestor
# check_local_user
file = .forward
modemask = 002
filter

specialgroups:
driver = smartuser
new_address = specialgroups@???
no_verify_recipient
no_verify_sender
suffix = ".*"

=========================

What I try to do is keep all emails which send to
specialgroups@??? that can still be received by POP3. But once
I setup IMAP, and don't create the Maildir for specialgroups, the mail
just gone somewhere I can not find. The test email not in the exim
queue, and not in /var/mail/specialgroups file. And not in
/var/spool/exim/input dir. I just can not find it.

Could anyone tell me how to make my specialgroups account still can
use pop3 to receive email but others use IMAP please?

Cheers,
--
Tao Lin