How to create a popover that listens to custom events

Question

I am trying to create a popover that I can open and close with my custom events. I tried to follow this answer and create my custom popover using:

.directive( 'myPopover', [ '$tooltip', function ( $tooltip ) {
  return $tooltip( 'myPopover', 'myPopover', 'openTrigger' );
}]);

But that didn't work.

I created a plnkr sample.