How do you backup the mail server?

How do you backup the mail server in 10.3? The manual kind vaguely says that you simply backup the mail server folder and its that easy. So thats all I've been doing, backing up /Library/AppleMailServer . Then the other day I had to restore from my backups, and it wasn't working. I couldn't get the server to use that folder at all. So I can't figure out what I'm doing wrong, but I also have no idea what the right way to back up mail is?