Just a tip as I didn't find any information on the forum and Kaseya support told me it couldn't be done.
When you look at historical data you can only choose the date and then how many hours back you want to see. Trouble is the timeframe is always from midnight which is awkard if you only want to see a couple of hours in the middle of the day.
However if you choose the date then edit the Start Date field you can put a space after the date and put the time in 24 hour notation eg: 14:00
So 11/6/2010 10:00 will show the time from 10am instead of midnight.