Changing the color of just one predefined state for a button.

I'm using a theme in my storyline which utilizes pre defined colors for the predefined states of buttons. The "Visited" and "Normal" state look exactly the same. I want to change the color of the "visited" state to something more pronounced. I don't no how to edit the button with out changing all of the states. Is this possible, is there a menu to edit states somewhere that I am not seeing? I have even tried creating a new state.