[Dovecot] Sieve not filtering

[Nicolas Mora]

Hello,

I installed a few weeks ago the Dovecot package on a Debian stable 
along with postfix, everything works fine except the sieve filter. I 
followed the howto found on the internet (google: debian postfix dovecot 
sieve). I'm able to view and modify sieve rules with roundcube or 
thunderbird plugins, but the rules are not applied when a message 
arrives and all messages arrive in INBOX. Here is the content of my 
configuration files concerning sieve :

dovecot.conf
protocols = imap imaps managesieve

    protocol managesieve {
      listen = *:2000
    }

protocol managesieve {
   mail_executable = /usr/lib/dovecot/managesieve

   managesieve_max_line_length = 65536

   managesieve_logout_format = bytes=%i/%o

}

protocol lda {
   postmaster_address = postmaster at babelouest.org

   mail_plugins = sieve
   mail_plugin_dir = /usr/lib/dovecot/modules/lda

   log_path =
   info_log_path =
   syslog_facility = mail
}

plugin {
   sieve_dir=~/Maildir/sieve
}


And the postfix/main.cf config file contains for dovecot sieve the 
following

maibox_command = /usr/lib/dovecot/dovecot-lda -f "$SENDER" -a 
"$RECIPIENT"
dovecot_destination_recipient_limit = 1
virtual_transport = dovecot

I also tried the command
mailbox_command = /usr/lib/dovecot/deliver

it didn't work either...

Is there somthing so obvious that I didn't see it ?

Thanks in advance