Out of Office / Autoreply – 10.3 Server – Squirrelmail?

Hi, I'm currently evaluating mailservers and want to set up an autoreply feature for Mac OS X 10.3 Server. I figured that the easiest route would be to add this feature somewhere in squirrelmail, as I already intend to use it for web based email and users can configure it theirselves without intervention of the admin. I have found out of office plugins for sendmail, but not for postfix. Are there people on this board who are using autoreply functionality on their mailserver? How did you solve this issue? A pointer in the right direction would be most helpful. Frederik