Sendmail "problem"

From: Raymond (r.visser_at_leaseplus.nl)
Date: 09/29/03 

Date: 29 Sep 2003 07:12:47 -0700

I have sendmail configured as Smart relay to our Notes server.
An application on AIX uses the sendmail buildup.
Everything works fine as long as users type legit email adresses.
Even the -f option works fine for the recipients and reply mail is
always delivered to the inbox on the notes server.

BUT, if an invalid email adress is entered, the notes server gets a
dead mail trying to send to <username>%<aix-host>@our-domain.nl.

It turns out that <username>%<aix-host> is the SMTP originator.
Is there a way to override this with the name given in the sendmail -f
option ?