jwplayer - change controls look when caption is on

Question

i'm building my own jwplayer skin (jwplayer 6) using xml file and i changed the look of the controls bar. when the caption is on i want the controls bar to look different. Is that possible?

I found this:

    events: {
            onCaptionsChange: function(event) {          
             }
   }

and i think i can add a class to the control bar and work with it with css but it doesn't feel right.