Cumulus Support

I recently switched from WD to Cumulus (very happy I did..!!)
Cumulus is running since May 6 2012 and shows Monthly rainfall as from that date.
However, the 19.2mm that fell in May before the 6th is not shown in Monthly total (Cumulus does not have a time-stamp from before May 6).
How and where do I correct the monthly total, so it will be correct (adding the 19.2mm).

Thanks,

Arthur

The monthly total is calculated from the daily totals in dayfile.txt, so the only way to change it is to either add in the extra amount to the existing entries, or create one or more extra entries.