[CentOS] cyrus-imapd, sendmail and delivering plus address formats

CentOS-4.8
cyrus-imapd-2.2.12-10
sendmail-8.13.1-3.3

I have a mail hub which uses cyrus-imap with sendmail  It has worked
well for us on this and prior hosts going back to 1995.  And, I do
not have a problem with the current setup.

What I would like to do however, is to deliver plus-formatted e-mail
addresses directly to users subfolders in their mailbox tree.  Such
addresses take the form
userid+subfolder+sub-subfolder at domainname.tld. How this is done I
have not discovered. What I always get is an  ".Address Unknown"
smtp error.

I have gone to both the cyrus and the sendmail lists respecting this
issue. While there is a lot of information there following any of it
does not seem to lead me anywhere fruitful.

Does anyone here run a sendmail/cyrus-imap combination on CentOS
that has direct delivery into user mailbox subfolders using the plus
address format working?  Is so, would you be so kind as to provide
an outline of how this is done?


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James B. Byrne                mailto:ByrneJB at Harte-Lyne.ca
Harte & Lyne Limited          http://www.harte-lyne.ca
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Hamilton, Ontario             fax: +1 905 561 0757
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