[Dovecot] LMTP Proxy auth

[claus.r at bayern-mail.de]

Hi,

i tried to use lmtp proxy to a cyrus-server where i need authentication.
My passdb lookup gives me:
user=mailbox at cyrus.serv.er    host=192.168.1.1      proxy=Y pass=secret  
      destuser=cyrus_lmtp_master

As i see in packettrace to the lmtp-cyrus-server the dovecot-proxy 
didn't try any authentication.

Could someone please confirm to me that LMTP proxy with auth isn't 
supported or is there any configuration issue i have missed?