You've probably already read the documentation available here ->
http://www.novell.com/documentation/ximian.html
though I couldn't find that answer. I posted over a year ago asking
how to change the smtp port, and bumped it a week ago, but no
one has responded to that either. Noticed you haven't had many
views in this thread.
It's now owned by Novell, who owns SuSE, so that's probably where
they'll give support - which negates all my interest in the product.
Sorry I can't help, unless you find something in that doc.