cyradm & allowplaintext: no

[Jorey Bump]

I'm trying to harden cyrus-imapd by disallowing unencrypted plaintext 
logins. Here is my imapd.conf:

configdirectory: /var/imap
partition-default: /var/spool/imap
# admins should not receive mail
admins: cyrus
sasl_pwcheck_method: saslauthd
sasl_mech_list: PLAIN LOGIN
tls_cert_file: /etc/ssl/certs/imapd.pem
tls_key_file: /etc/ssl/certs/imapd.pem
# don't allow plaintext logins without STARTTLS or encryption
allowplaintext: no

This works as expected, but now I can't login with the command line cyradm:

cyradm -u cyrus example.com
IMAP Password:
               Login only available under a layer at 
/usr/local/lib/perl5/site_perl/5.8.7/i686-linux/Cyrus/IMAP/Admin.pm line 118
cyradm: cannot authenticate to server with  as cyrus

When I change allowplaintext to yes, it works again. I don't want to 
allow users to send their passwords in the clear, but I want to 
administer cyrus from the command line. Is there a way to do this?