[Dovecot] Dovecot + Sieve does not work

[Jimmi]

 Hi,

 On my Debian Squeeze server I installed Dovecot 1.2.16 from 
 http://xi.rename-it.nl/debian/ and configured as follow:
 # dovecot -n
 # 1.2.16: /etc/dovecot/dovecot.conf
 # OS: Linux 2.6.26-110209 i686 Debian 6.0 ext3
 log_path: /var/log/dovecot.log
 log_timestamp: %Y-%m-%d %H:%M:%S
 protocols: imap sieve
 disable_plaintext_auth: no
 login_dir: /var/run/dovecot/login
 login_executable: /usr/lib/dovecot/imap-login
 first_valid_uid: 100
 mail_privileged_group: postfix
 mail_location: maildir:/home/virtual/%d/%n
 mbox_write_locks: fcntl dotlock
 imap_client_workarounds: outlook-idle
 lda:
   postmaster_address: postmaster at 7girello.net
   mail_plugins: sieve
   log_path: /var/log/dovecot-deliver.log
   info_log_path: /var/log/dovecot-deliver.log
 auth default:
   mechanisms: plain login
   user: postfix
   passdb:
     driver: sql
     args: /etc/dovecot/dovecot-mysql.conf
   userdb:
     driver: sql
     args: /etc/dovecot/dovecot-mysql.conf
   socket:
     type: listen
     client:
       path: /var/spool/postfix/private/auth
       mode: 432
       user: postfix
       group: postfix
     master:
       path: /var/run/dovecot/auth-master
       mode: 384
       user: virtual
       group: virtual
 plugin:
   sieve: /home/virtual/%d/%n/.dovecot.sieve
   sieve_dir: /home/virtual/%d/%n/sieve/

 After that in Roundcube 0.5.1 downloaded from http://roundcube.net/ I 
 enabled the managesieve plugin but when I go to the filter page RC says 
 that he cannot connect the server. I then realized that the port 4190 is 
 not open and I cannot understand why.

 In my dovecot.conf I have the section:
 protocol managesieve {
   # Specify an alternative address:port the daemon must listen on
   # (default: *:2000)
   listen = localhost:4190
 }

 that is not shown in the output of 'dovecot -n'.

 Did I missed something?

 Thanks in advance
-- 
 jimmi