[exim] return path for nobody user

Hi

I have been having some problems with regards bounce back emails.
When I am sending emails via apache webserver the bounce back sends it to
nobody account.
I found out that if i pass parameters -f and then emailaddress then this
problem is solved and bounce back is sent to proper email address.
But I cant possibly change all the code on the server. Is it possible for me
to solve this problem by making some configuration changes in exim.conf


Best Regards,
Kailash