How do I make it so the detail band is always a certan height?

I'm printing on a preprinted form. At the bottom, I have a field preprinted that says "Totals". So in the detail I list the items and at the bottom, I have it print totals. This shouldn't be very hard. I'm sure many people have done this before. When it currently prints, it moves the totals up right underneath the last line of the detail.

Any help would be greatly appriciated.

-Robert Hamilton