[tlug] Postfix bounced e-mail / alias message

[patrick.niessen@example.com]

I have installed Postfix and Amavis / SpamAssasin, and setup the mail
aliases in a mysql database. 

The problem I have is that mail that is recognised as invlid is bounced with
a message that reveals the final alias. Eg.  a spam mail sent to
patrick@example.com gets bounced but the info text includes the text "...
Final recipient user00023@example.com", ideally the bounce message should
only mentioned the original RCPT address ie, patrick@example.com

Any ideas of how to modify postfix?

cheers

patrick