[CentOS] Sendmail-SMTP, Cyrus-IMAPD and plus (+) addressing.

Has anyone on this list got sendmail and cyrus-imapd configured so
that email addressed in the form username+folder at example.com gets
delivered directly to cyrus' user.username.inbox.folder?

I have been tinkering with this on and off for about a week and no
matter what I have tried, all traffic addressed in the +folder
format ends up in user.username.inbox instead.

If anyone has gotten this to work then I would very much appreciate
knowing the exact steps that you followed to implement it.

1. I am not changing smtp MTAs, the legions of fans of qmail and
postfix notwithstanding.

2. Ditto for imap and dovecot.


-- 
***          E-Mail is NOT a SECURE channel          ***
James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
Harte & Lyne Limited          http://www.harte-lyne.ca
9 Brockley Drive              vox: +1 905 561 1241
Hamilton, Ontario             fax: +1 905 561 0757
Canada  L8E 3C3