Hopefully this can help you get started in the right direction: http://www.finalemusic.com/blog/setting-custom-percussion-staff-finale/

whoops, that's for 2014. Let me open my 2011 and give you a better answer!

So, select the staff tool and then control + click (right click) the handle of the percussion staff and Select "Select percussion Layout" form the menu that appears.

Then, in that link I posted, if you skip to the part "Under the Instrument List tab, select the Percussion staff and click the Settings button near the Notation Style pop-up menu. This is where the fun begins. Welcome to the Percussion Layout Selection dialog box:" everything should still be correct.

Hope that helps!