Configuring Postfix to use milter (archiveSMTP)

How does one config Postfix to use the milter "archiveSMTP" ?

The milter config instructions (http://www.dancingfortune.com/projects/archivesmtp/download.php) mention only one socket for communication between the milter and the MTA

… yet any Postfix docs I read use two sockets – one for the milter to listen on for messages from the Postfix queue and a second for reinjection back in to the Postfix queue.

So following a Postfix tutorial (Postfix: The Definitive Guide) I add

 archive   unix  -       -       n       -       10              smtp 
    -o myhostname=localhost

to master.cf for messages to the milter. And enable this in main.cf with

   content_filter = archive:[127.0.0.1]unix:/var/run/archivesmtp/mta.sock

(I'm reasonable sure this is correct as the archiveSMTP documentation gives a Sendmail example and calls this socket (unix:/var/run/archivesmtp/mta.sock) the Input MailFilter)

The Postfix tutorial goes on to define another socket (in inet format this time) like so:

 localhost:10026 inet n  -  n -  10 smtpd

(again in master.cf)

for the reinjection to the Postfix queue.

…except archiveSMTP makes no mention of a second socket.