[exim] exim4 and amavisd-new on seperate servers

Hello,

I am trying to configure exim4 + amavisd-new to work on seperate servers. At present I am running both process on a single server, routing via smtp through exim, onto amavisd-new and then back to exim on port 10025. Due to the high load on the server caused by the scanning, I would like to off load the scanning process to a different server.

So far I have managed to get the new scanning server to forward it's processed mails to the existing server for delivery. However, I am hitting dead-ends when I try to get the exim server to forward everything via the amavis director (or is it router?) to the new scanning server, and then back to the first server, but on the second port.

Has anyone managed to do this and have any suggestions how I modify my configuration? The new server Ip is 192.168.1.13 and amavis is listening on 10024, my current router, director and transport confs are as follows:

Trransports:

amavis:
       driver = smtp
       port = 10024
       allow_localhost

amavis_smtp:
    driver = smtp
    hosts = localhost
    port = 10024
    allow_localhost
      hosts_override

Director:

amavis_director:
  driver = accept
  #condition = "${if eq {$received_protocol}{scanned-ok} {0}{1}}"
  condition = "${if or {{eq {$received_protocol}{scanned-ok}} \
                                 {eq {$sender_host_address}{127.0.0.1}}}\
                                 {0}{1}}"

retry_use_local_part
#transport = amavis
transport = amavis_smtp
#transport = remote_smtp
no_verify

Router:

(this is the first router in the list)

amavis:
        driver = manualroute
        # condition = "${if eq {$interface_port}{10025} {0}{1}}"
        condition = "${if or {{eq {$interface_port}{10025}} \
                          {eq {$received_protocol}{spam-scanned}} \
                          {eq {$sender_address}{}} \
                         }{0}{1}}"
    # if scanning incoming mails, uncomment the following line and
        # change local_domains accordingly
        domains = ! +local_domains
        transport = amavis
        #transport = remote_smtp
    route_list = "* localhost byname"
        self = send

Thanks to anyone that can throw some light on this!

regards

Richard