1. cp -a /etc/cpanel_exim_system_filter /etc/cpanel_exim_system_filter_modified

2. Add the following to /etc/cpanel_exim_system_filter_modified

#Incoming/Outgoing Email Archiving
if ("$h_to:, $h_cc:, $h_bcc" contains "domain.com")
then
unseen deliver "incoming@domain.com"
endif

if $sender_address_domain is domain.com
then
unseen deliver "outgoing@domain.com"
endif

3. Go to Main » Service Configuration » Exim Configuration Manager and modify the System Filter File line to: /etc/cpanel_exim_system_filter_modified then click Save.