sendmail not authenticating

I'm having trouble getting cyrus sasl to work with sendmail on debian.

I have sendmail offering authentication:

250-AUTH LOGIN PLAIN DIGEST-MD5 CRAM-MD5

and I have this in the /etc/mail/sasl/Sendmail.conf.2 (and this file is
also symlinked to from /usr/lib/sasl2/Sendmail.conf:

pwcheck_method:saslauthd

testsaslauthd with a valid username and password returns
0: OK "Success."

If I run saslauthd in debug mode, I clearly see the testsalsauthd
request/response.  However, when I use sendmail to authenticate, I see
nothing.  Even if I try the authentication in sendmail by hand (i.e. by
crafting the base64 username and password).

Nothing useful in the logs.

It's as if sendmail isn't even trying to contact saslauthd, yet it is
offering those possible auth methods above.

Any ideas?  Any clues as to how to get sendmail to tell me what it's doing
or not doing with respect to authentication?

Michael Grant