Hide & Show Navagation buttons

If you are not using SWF, this JavaScript entered in the script window on slide enter will do the trick.

Populate the variable rollArray with a 0 for each element you need to roll over, in this instance it's 3.

Add an event listener for each of the roll over names in bold below. Put the name of the next button in the cp.show command.

var rollArray=[0,0,0];

document.getElementById("Rollover_Area_1").addEventListener("mouseover",rollOver,false);
document.getElementById("Rollover_Area_2").addEventListener("mouseover",rollOver,false);
document.getElementById("Rollover_Area_3").addEventListener("mouseover",rollOver,false);

function rollOver(event)
{
var idx=event.target.id.split("_");
rollArray[idx[idx.length-1]-1]=1;

if (rollArray.indexOf(0)==-1)
{
  cp.show("next_btn")
}
}

You cannot do that out of the box, because rollover for a rollover image is not an event. Rollover exists as event for a rollover slidelet, which could trigger an conditional action. But why still bother with rollovers, since they are not supported for responsive projects?