[exim] Undeliverable message as well as catch all

Hi,

Im hoping someone can help,

I currently have an exim setup where all incoming mail is automatically
routed to separate servers according to a user list text file using the
manualroute driver. I have a 'catch all' transport where any mail that
cannot be routed gets sent to a local 'junkmail' file using the appendfile
driver.


###########CATCH ALL
local_delivery:
driver = appendfile
file = /var/mail/junkmail
delivery_date_add
envelope_to_add
return_path_add
group = mail
mode = 0777

My question is how can I setup it up so that a Undeliverable message is sent
to the sender when mail ends up in the junkmail file.

Thanks,

Michael.