[Dovecot] master password 'username contains disallowed character: 0x2a'

[Dale Bewley]

v1.0.rc22 FC6 x86_64

So, here is my config:
protocol imap {
}
protocol pop3 {
}
protocol lda {
  postmaster_address = postmaster at example.com
}
auth_master_user_separator = *
auth_verbose = yes
auth_debug = yes
auth_debug_passwords = yes
auth default {
  mechanisms = plain
  passdb passwd-file {
    args = /etc/dovecot.masterusers
    master = yes
  }
  passdb pam {
  }
  userdb passwd {
  }
  user = root
}
dict {
}
plugin {
}

But here is what happens when I try to login as dlbewley*zimbra using
the password I put in dovecot.masterusers.

Feb 16 23:37:30 tofu dovecot: Dovecot v1.0.rc22 starting up
Feb 16 23:37:31 tofu dovecot: auth(default): passwd-file /etc/dovecot.masterusers: Read 1 users
Feb 16 23:37:49 tofu dovecot: auth(default): client in: AUTH    1       PLAIN   service=IMAP    secured lip=::ffff:169.237.1.109   rip=::ffff:169.237.2.160
Feb 16 23:37:49 tofu dovecot: auth(default): client out: CONT   1
Feb 16 23:37:49 tofu dovecot: auth(default): client in: CONT    1       ZGxiZXdsZXkqemltYnJhAGRsYmV3bGV5KnppbWJyYQBjb2tlc2hpdDc=
Feb 16 23:37:49 tofu dovecot: auth(default): plain(zimbra,::ffff:169.237.2.160): login user: Username contains disallowed character: 0x2a
Feb 16 23:37:49 tofu dovecot: auth(default): client out: FAIL   1       user=zimbra
Feb 16 23:37:49 tofu dovecot: imap-login: Disconnected: user=<zimbra>, method=PLAIN, rip=::ffff:169.237.2.160, lip=::ffff:169.237.1.109, TLS

If I try setting this:
auth_username_chars =

I get this:
Feb 16 23:45:15 tofu dovecot: Dovecot v1.0.rc22 starting up
Feb 16 23:45:16 tofu dovecot: auth(default): passwd-file /etc/dovecot.masterusers: Read 1 users
Feb 16 23:45:22 tofu dovecot: auth(default): client in: AUTH    1       PLAIN   service=IMAP    secured lip=::ffff:169.237.1.109   rip=::ffff:169.237.2.160
Feb 16 23:45:22 tofu dovecot: auth(default): client out: CONT   1
Feb 16 23:45:22 tofu dovecot: auth(default): client in: CONT    1       ZGxiZXdsZXkqemltYnJhAGRsYmV3bGV5KnppbWJyYQBjb2tlc2hpdDc=
Feb 16 23:45:22 tofu dovecot: auth(default): passdb(zimbra,::ffff:169.237.2.160,master): Master user logging in as dlbewley*zimbra
Feb 16 23:45:22 tofu dovecot: auth(default): client out: OK     1       user=dlbewley*zimbra
Feb 16 23:45:22 tofu dovecot: auth(default): master in: REQUEST 1       7537    1
Feb 16 23:45:22 tofu dovecot: auth(default): passwd(dlbewley*zimbra,::ffff:169.237.2.160): unknown user
Feb 16 23:45:22 tofu dovecot: auth(default): userdb(dlbewley*zimbra,::ffff:169.237.2.160): user not found from userdb
Feb 16 23:45:22 tofu dovecot: auth(default): master out: NOTFOUND       1
Feb 16 23:45:22 tofu dovecot: imap-login: Internal login failure: user=<dlbewley*zimbra>, method=PLAIN, rip=::ffff:169.237.2.160, lip=::ffff:169.237.1.109, TLS