I need to find the number of days and hours between a start date and an end date on a leave from:

6/13/11 8:30 a.m to 6/14/11 1:30 p.m.

The problem is that I don't want the total days and hours. the normal subtraction formula would give me 29 hours. I need to know the time used between the business hours of 8:30 a.m. thru 5:30 p.m., not a 24 day. (in that case 14 Hours)

thank you