Postmaster to remove MAILER-DAEMON mail

Hi all,

I'm on 10.3.9 ( XServe G5 Dual 2ghz + Xraid 5,6To )

I need to store MAILER-DAEMON mail into a folder ( or on a mailbox )
my server get MAILER-DAEMON mails but i can't store them

I can see that i have MAILER-DAEMON mails using mailq command with this command line:

xserve:~ admin$ mailq | grep MAILER-DAEMON | wc -l
353

So i have acutally 353 MAILER-DAEMON in queue

if i look at my aliases file i have ( more /etc/aliases )

# Basic system aliases -- these MUST be present
MAILER-DAEMON: postmaster
postmaster: root

# General redirections for pseudo accounts
bin: root
daemon: root
named: root
nobody: root
uucp: root
www: root
ftp-bugs: root
postfix: root

# Put your local aliases here.

# Well-known aliases
manager: root
dumper: root
operator: root
abuse: postmaster

# trap decode to catch security attacks
decode: root

if i send a mail to root, admin, postmaster, MAILER-DAEMON, abuse , all mails are forwarded to my mail and can look them.

but i don't have MAILER-DAEMON mails :(:(

I had an entry into admin server in mail > settings > copu underlivery mails to =====> postmaster
but i have the same result if i remove this

how to get MAILER-DAEMON mails and store them ?
I need them to lunch a script who give me a list off all mails which failed.

If you have a software who do it simple ( Application, not an OS install ) i think this is the best way.

How to use the newaliases command ? ( maybe this don't work beacause i lunch a bad command )

Thx for help