param options.value from DropDownList.virtual.valueMapper does not work on kendo ui 015.2.624

Hi, 

 When I updated my kendo ui lib from version v2015.1.429 to v2015.2.624 the DropDownList configuration, virtual.valueMapper, is not working anymore. To be more exact, the parameter option.value is not retrieving the selected value from the dropdown list anymore. 

HTML:

  <input type="text" class="total-width-impt" kendo-drop-down-list k-options="fenceDropDownOptions" k-data-source="fences" name="origin_fence" data-bind="value:origin_fence_id">

 Javascript:

 $scope.fences =[...]

$scope.fenceHash = [...]

fenceOptions =
    dataTextField: 'label'
    dataValueField: 'id'
    delay: 500
    minLength: 3
    filter: 'contains'
    virtual:
      valueMapper: (options) ->
        options.success($scope.fenceHash[options.value].sort_index)
    dataSource:
      pageSize: 100