Ubuntu 9.04, Postfix, Dovecot, Squirrelmail, and vacation/away messages
Solution 1:
Glad the walkthrough was helpful. While not a perfect solution, (considering you're using Squirrelmail) I did just post a followup on implementing postfixadmin's virtual vacation plugin. http://craigballinger.com/blog/2009/08/postfix-vacation-autoresponder/ It should at least give you an option if you haven't found a solution yet. I'm currently writing a plugin for roundcube's webmail app that will give users access to the autoresponder functionality from inside their webmail. Hopefully the first build of that isn't too far out.