[Exim] exiscan - notify recipient if mail is rejected

hi!

I've just insalled Exim4 and I'm trying to get the setup perfect. Does
anybody know how I can get exim til send a notification mail to the
recipient of a rejected mail, so the recipient can be told that "you
recieved a mail containing a virus from ...." and then just reject the
incomming mail? Should this be done in the "reject" phase of exiscan or
during delivery of the mail? Do I need to activate the perl library?

regards
Asbjørn