There are no silly questions, Supe; only silly answers .
When I install a new box I install ClamAV following the instructions here and then I install the appropriate version of SpamBlocker3 and of course the required exim.pl, from my site here.
I edit the SpamBlocker3 file to show (in the event of a false positive) the link to your own page instead of example.com, and since I run ClamAV I add that extra file (see #3 below).
...and of course the required exim.pl, from my site