Setting Exim to log to In and Out files?

Hi,

I'm looking to write a script that parses the Exim mainlog and reports mail counts in/out to mrtg to be graphically displayed. Is there anyway to tell Exim to log to mainlog.in and mainlog.out or similar?

Thanks !

http://www.roads.lut.ac.uk/txt/exim-mrtg.html

Some paths probably need adjusting.

John