Angular.js angular-dragdrop custom callback function not found

I'm using this plugin with Angular. In the documentation it says that

onDrop callback method to be invoked a draggable is dropped into the droppable

so I tried using it like this (the relevant part is the onDrop="myCallback"):

<div class="thumbnail" data-drop="true" 
        onDrop="myCallback" ng-model='list1' 
        data-jqyoui-options="optionsList1" 
        jqyoui-droppable="{multiple:true}">
    <div class="caption">
        <div class="btn btn-info btn-draggable" 
              ng-repeat="item in list1" 
              ng-show="item.title" 
              data-drag="{{item.drag}}" 
              data-jqyoui-options="{revert: 'invalid'}" 
              ng-model="list1" jqyoui-draggable="{index: {{$index}},animate:true}">                
        {{item.title}}
        </div>
    </div>
</div>

And defined the function on the scope like so:

$scope.myCallback = function(event, ui){
    console.log('Dropped into something');
};

http://plnkr.co/edit/kiYrIU?p=preview

As you can see from the Plunker, this doesn't work, for some reason the callback function isn't found (it's not looking on the scope perhaps?).

I have tried multiple variations of this, like onDrop="myCallback(event, ui)" or onDrop="myCallback" etc. None of these worked.

Is this a bug or am I simply not using it correctly?

Thanks in advance.