Well I am not sure whether I got you problem or not but I think you want to customize particular Richfaces component so I think you can write your own custom style classes in your CSS for that component for that you can refer developer's guide for Definition of Custom Style Classes.
Hope it will help.
I'm afraid he is not about styleClasses but about js.. So in your case - you should check out our sources abd patch concrete component js. Read in our wiki about our SVN and components building.