Bounce Messages

[Daniel Hardaker]

Im looking to get rid of my catch all (postmaster) account on one of my
domains due to a massively high volume of spam sent to [EMAIL PROTECTED] .
However, im worried that genuine email will be bounced so I would like to
add a bit to the 'No Mailbox here by that name' bounce message saying how to
get help if the email is genuine.  I cant find the text for this bounce
anywhere, where abouts are they stored?

Thanks!