dovecot - Apr 2009 - [TroubleShoot]How to know what problem with Dovecot-POP3 configuration?

Hi all,

I am using Ubuntu8.04/Dovecot 1.0.10 and the dovecot -n shows as following,
-----------------------------------------------------------------------
# 1.0.10: /etc/dovecot/dovecot.conf
log_timestamp: %Y-%m-%d %H:%M:%S
protocols: imap imaps pop3 pop3s
disable_plaintext_auth: no
login_dir: /var/run/dovecot/login
login_executable(default): /usr/lib/dovecot/imap-login
login_executable(imap): /usr/lib/dovecot/imap-login
login_executable(pop3): /usr/lib/dovecot/pop3-login
mail_privileged_group: mail
mail_location: maildir:/home/%u/Maildir
mail_executable(default): /usr/lib/dovecot/imap
mail_executable(imap): /usr/lib/dovecot/imap
mail_executable(pop3): /usr/lib/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/modules/imap
mail_plugin_dir(imap): /usr/lib/dovecot/modules/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/modules/pop3
pop3_uidl_format(default):
pop3_uidl_format(imap):
pop3_uidl_format(pop3): %08Xu%08Xv
auth default:
  mechanisms: plain login cram-md5 digest-md5
  verbose: yes
  debug: yes
  passdb:
    driver: passwd-file
    args: /etc/dovecot/plain.pwd
  passdb:
    driver: pam
  userdb:
    driver: passwd
-----------------------------------------------------------------------
PROBLEM -
[1] I cannot get the full CAPABILITY list after the user1/user1 login which
includes plain login cram-md5 digest-md5,  while can get a full complete list if
I don't do the user1/user1 login when telnet at 143
      But       - auth connect from thunderbird client to IMAP4 email server
successful for CRAM-MD5 for user1/user1, as seen from /var/log/mail.log
[2]I cannot see the CRAM-MD5 and APOP auth connect logging in /var/mail/mail.log
or mail.info when doing connect to Dovecot POP3 from thunderbird client
        - connect from thunderbird is successful but there is no logging info
related with pop3-login in /var/log/mail.log or mail.info

Can anyone tell me why I cannot see the logging for Dovecot Pop3 in the
/var/log/mail.log or /var/log/mail.info and it seems there is no info shown for
the POP3 CRAM-MD5 authentication?

Thanks.