Button rollover action in Captivate 8 Responsive project

Hello,

   I am new to Captivate 8. I want to setup a rollover action to change the text in a text box. Thus, when they rollover each button, they can see the action that the button will take. I have created two image buttons and enabled rollover; but am unable to tell how to set the text variable to the value of the rolled over button. I am unable to find a 'rolled-over' action in the advanced actions script. In researching this issue, I see different statements indicating that this can not be accomplished, yet the Adobe help text eludes to that fact that it can be done. I am unable to create a rollover slidelet as that option is shaded out.

Thanks,

Peter