[Dovecot] Log DNS revese IP address

[Juan Bernhard]

Hi list. Is it possible to log the DNS reverse address of every login?
I didnt find a variable *%{hostname}* but the wiki say it only works on 
*deliver_log_format* and not on *login_log_format_elements*

Something like this:
Mar 21 13:49:33 mailserver dovecot: pop3-login: Login: user=<myuser>, 
method=PLAIN, rip=10.10.10.15, lip=10.10.10.1, mpid=18712, 
*host=client02.example.com*

Thanks!

Regards. Juan