Above site does explain the switches. In the "Installation instructions" section you find all information:
Check the following options of the imapd.conf file. createonpost : It must be "yes" in order to activate patch operations,
when an incoming message arrives (LMTP). (default = no)
[...]
You also need to tell sendmail to first check if the user exists (default option for cyrus* mailers is not to check). Or you will get new mailbox created for each and every mistyped and/or nonexistant email address.
-- Aleksandar Milivojevic <amilivojevic@xxxxxx> Pollard Banknote Limited Systems Administrator 1499 Buffalo Place Tel: (204) 474-2323 ext 276 Winnipeg, MB R3T 1L7
