Best way to move spam mail to a folder readable by users

I search the best way to move spam mail to a folder readable by users.

On other server.. i have email [email protected] and alll spam are go on it.
But i don't know how i can install it with ispconfig and postfix

I use SquirelMail, because it's on installation by default. I use the Centos OS.
On other server i use roundcube.
It's possible to easy add pluggin in squirelmail ? Because i dont want scrap ispconfig.

 

I think you can configure this in the amavisd configuration.

 

I think i can use this config in amavisd

$QUARANTINEDIR = "/var/virusmails";

If i create email account like this : [email protected]
and i create link of /var/virusmails in /var/vmail/domainname.com/spam/new/

Do you think it's work ?
One of the probleme is the spam mail are in .gz format