[exim] Not allow smtp email relay to external server.

Hi,

The Exim server (version 4) is able to send email from local nework to
external mail server, but when external client connect (login and
authenticated with the user name) to this Exim server and try to use it
to relay email to an external mail server, the Exim server does not
allow email relay. I thought the following setup will redirect smtp
authentication to cyrus lmtp:
In ROUTER:
localuser:
driver = accept
# check_local_user
# local_part_suffix = +* : -*
# local_part_suffix_optional
transport = local_delivery_lmtp
cannot_route_message = Wonderful - Unknown user
In TRANSPORT:
local_delivery_lmtp:
driver = lmtp
batch_max = 20
socket = /var/spool/imap/public/lmtp
timeout = 45s
group = mail
user = cyrus


but apparently it does not, the message indicated there must be some
other setup in the following codes:

acl_check_rcpt:
accept  hosts = :
deny    message       = Restricted characters in address
          domains       = +local_domains
          local_parts   = ^[.] : ^.*[@%!/|]
  deny    message       = Restricted characters in address
          domains       = !+local_domains
          local_parts   = ^[./|] : ^.*[@%!] : ^.*/\\.\\./
  accept  local_parts   = postmaster
          domains       = +local_domains

  require verify        = sender
  accept  domains       = +local_domains
          endpass
          verify        = recipient

  accept  domains       = +relay_to_domains
          endpass
          verify        = recipient
  accept  hosts         = +relay_from_hosts
  accept  authenticated = *
  deny    message       = Wondeful - relay not permitted
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                            here is where it causes relaying denied.

I don't use MySQL and LDAP, only login is authenticated thru
cyrus-sasl2. So how can I setup smtp authentication to allow
authenticated email relaying in this case?
I have verified that the email client (mozilla) have the check-box of
Use name and password checked and I have typed in the user name in the
edit box as well.

Thanks
Sam