Dashboard Button?

Hi everyone. I'm running Mountain Lion and I prefer the dashboard to "come down" over whatever I'm doing rather than it having it's own space. I this option off in the "mission control" section part of the dashboard, which I noticed also has some options to set shortcuts to the dashboard. This would be just perfect except for the fact that none of the shortcuts work, except for using the mouse button. Basically I want to remap the F4 button so it opens dashboard instead of launchpad. Does anyone else have this problem or a fix?