How to permanently disable "failure notice" qmail bounce mails @ plesk?

[applestar]

Well, well. After an autoupdate few days ago our qmail mail server starts to send "failure notice" (backscatter) emails all over the world again.

e.g.
------- cut here ------

"Hi. This is the qmail-send program at xxx.dedicated.hosteurope.de.
I tried to deliver a bounce message to this address, but the bounce bounced!

<spammer@spammer.sp>:
xx.xx.xx.xx does not like recipient.
Remote host said: 550 RCPT TO:<spammer@spammer.sp> User unknown
Giving up on xx.xx.xx.xx."
------- cut here ------

I would LOVE to see a general ON/OFF switch for all email bounce notifications on Plesk, since the problem bothers a lot of users. But since it does not seem to happen, please provide a way to deactivate bounces.

(I am not interested in forwarding all email to some catch-all, I really just want qmail to be quiet!)

System: Plesk 10.2.0 on Ubuntu Hardy

 

[applestar]

Adding: It is not about non-existent users (they are handled with http://kb.odin.com/en/1376)