Dovecot : déplacer les SPAM dans un dossier avec un filtre sieve

root@mail:/# cat /var/spool/vmail/sieve/global.sieve

require "fileinto";

if exists "X-Spam-Flag" {
    if header :contains "X-Spam-Flag" "YES" {
        fileinto "Spam";
        stop;
    }
}
root@mail:/# cat /etc/dovecot/dovecot.conf
protocol lda {
  mail_plugins = sieve
}

plugin {
  sieve_before = /var/spool/vmail/sieve/global.sieve
  sieve = /var/spool/vmail/%d/%n/user.sieve
  sieve_global_dir = /var/spool/vmail/sieve/
  sieve_dir = /var/spool/vmail/%d/%n/
}