I'm trying to create a formula which calculates the business hours (8am - 5pm) between a task being created and closed.

I created a custom "ClosedDate" field on the task object.

I found an example online: http://help.salesforce.com/apex/HTViewSolution?id=000089863&language=en_US

I tested creating a task today (Oct. 28) and closing it with a date of Oct. 30th.  The number of hours shown the formula field displayed 36 hours.  It should only show the business hours between 8am and 5pm and exclude weekends.  Is there a way to adjust the formula in the link above to accommodate those requirements?

Thanks for any help!