[Dovecot] LMTP Proxy not logging users' IP

[Luca Palazzo]

Hi All,
is there any way to enable logging of users' IP address in dovecot 
director host?
It actually logs only:
Sep 14 07:32:29 mailgw-lb dovecot: lmtp(17615): Connect from xx.xx.xx.xx
Sep 14 07:32:29 mailgw-lb dovecot: lmtp(17615): Disconnect from 
xx.xx.xx.xx: Client quit

Thanks
Luca