Postfix and Canonical mapping

Maybe it’s just me, but when I enable canonical mapping, SMTP stops responding and all connections time out. I noticed the module config help is looking for /etc/mail/canonical but the default is /etc/postfix/canonical.
Essentially what I want to do is map user.domain@hostname to the primary e-mail address for the account so Squirrelmail, Horde, and scripts work automatically. I noticed someone posted a regexp but unfortunately my user names only include the prefix and it would be a couple of hundred to change.
Any help would be greatly appreciated