Ionic-datepicker callback not fired

Hello ionic-people,
i have another question. This time it is the ionic plugin from rajeshwarpatlolla (https://github.com/rajeshwarpatlolla/ionic-datepicker).

Now i tried some different approaches but it wont do what i want.

Actually i want the datepicker to display and after i click on “ok” i want that my callback function is fired. But it wont.

This is my code:
$scope.datepickerObject = { callback: function (val) { //Mandatory console.log("Im in callback"); }, };

And this is the code in my view:
<ionic-datepicker input-obj="datepickerObject""> <div> {{item.reserve.from}} </div> </ionic-datepicker>

It just fired an callback when i write it as an HTML-Tag. But this isnt what i want, because i want specify the datepicker within the scope object.

Does someone know’s where my mistake is?

Sincerly,
Alex