sendmail, pam, saslauthd, and cyrus-imapd

Hey all,

I've got a small system that I'm trying to configure using sendmail and 
cyrus. I want my users to exist as accounts (to support procmail scripts 
for my users, I hope), and I'd like to use PAM to authenticate. I'm 
running linux 2.4.18 on i686, sendmail 8.12.5, cyrus-imapd 2.1.11, 
saslauthd 2.1.10. I'm totally new to cyrus-imapd and probably a sendmail 
novice, too.

I've gotten imapd working, at least to the point where I can log in 
using an IMAP client and get authenticated. There's no inbox, but I can 
add my own mailboxes through the IMAP client. I've run saslpasswd2 to 
create an account with the same user name as exists in PAM (is that the 
right thing to do?).

I'm running 'saslauthd -a pam'. imapd.conf is set to use saslauthd as 
the pwcheck_method.

I'm using the default cyrus.conf, and master is running.

When I try to send mail to that account using sendmail, I consistently get:

Jan 29 14:27:16 satchel sendmail[8093]: h0TKRGvv008093: 
to=<bkoehn@xxxxxxxxxxxxxxxxx>, delay=00:00:00, xdelay=00:00:00, 
mailer=cyrus, pri=90355, relay=localhost, dsn=5.1.1, stat=User unknown

I'm using a more-or-less standard .mc file for sendmail:

VERSIONID(`my cyrus imapd implementation')

OSTYPE(linux)
define(`confBIND_OPTS',`-DNSRCH -DEFNAMES')
define(`confTO_IDENT',`0')

define(`confLOCAL_MAILER', `cyrus')
FEATURE(`accept_unresolvable_domains') dnl Just added
dnl this but to of no avail.
FEATURE(`nocanonify')
FEATURE(`always_add_domain')
MAILER(`local')
MAILER(`smtp')

MAILER_DEFINITIONS
Mcyrus,         P=[IPC], F=lsDFMnqA@/:|SmXz, E=\r\n,
                S=EnvFromL, R=EnvToL/HdrToL,
                T=DNS/RFC822/X-Unix,
                A=FILE /var/imap/socket/lmtp

LOCAL_RULE_0
Rbb + $+ < @ $=w . >        $#cyrusbb $: $1

I worry about that last line referencing cyrusbb, if that's interfering 
with PAM somehow. I also worry about not using cyrusv2 as the mailer, 
but could find no information on how to configure it correctly. I've 
tried changing the above mc file to use cyrusv2, but to no avail 
(although somedown I don't think I need the MAILER_DEFNINITIONS or 
LOCAL_RULE_0 with cyrusv2).

I've searched the FAQ and mailing list archives for days, and tried 
everything I can think of, but no luck. Anyone have any ideas? Thanks!