Altering the iPhone keyboard layout?

[hank863]

I was wondering if there is any way I can change what the keyboard layout for when someone clicks on my UISearchBar. I'd like to change the "space" bar into an "underscore" bar. I'd also like to change the "search" button into a "done" button. I know you can do that with a UITextField, but I want to use a UISearchBar for the appearance.