[Dovecot] Proxy config help please

[Zac Israel]

Hello, I am new to dovecot and I am initially trying to setup a basic
imap proxy with password forwarding, I can start the dovecot service,
connect and give it my password, and that is where I hang.  My config
is:

root at imap-test:/etc/dovecot# doveconf -n
# 2.0.19: /etc/dovecot/dovecot.conf
# OS: Linux 3.2.0-24-generic x86_64 Ubuntu 12.04 LTS
auth_debug = yes
auth_verbose = yes
debug_log_path = syslog
first_valid_uid = 100
imap_capability = CAPABILITY IMAP4rev1 ACL BINARY CATENATE CHILDREN
CONDSTORE ENABLE ESEARCH ESORT I18NLEVEL=1 ID IDLE LIST-EXTENDED
LIST-STATUS LITERAL+ LOGIN-REFERRALS MULTIAPPEND NAMESPACE QRESYNC
QUOTA RIGHTS=ektx SASL-IR SEARCHRES SORT THREAD=ORDEREDSUBJECT UIDPLUS
UNSELECT WITHIN XLIST
last_valid_uid = 200
mail_debug = yes
mail_gid = 107
mail_uid = 107
passdb {
  args = proxy=proxy_always nopassword=y host=172.16.0.13 port=143
proxy_timeout=5 starttls=y ssl=any-cert
  driver = static
}
protocols = imap
service imap-login {
  inet_listener imap {
    address = *
    port = 143
  }
}
ssl = required
ssl_cert = </etc/courier/imapd.pem
ssl_key = </etc/courier/imapd.pem
verbose_ssl = yes

The system at 172.16.0.13 is a zimbra proxy.  I can see in the logs
that it initially complains about my ssl cert, and if I remove
ssl=any-cert it fails because my cert is self signed, so I know it is
talking to the proxy and doing starttls which is a requirement of
zimbra.  Unfortunately I have not found a way to see the full exchange
between dovecot and my zimbra proxy other than tcp dump, which just
shows a small packet exchange.  Please let me know if I can provide
any other information and thanks in advance for any help.

-Zac