Accessing remote hierarchical treeview dataitem

I need help. The coding below run perfectly with local data but when implement it with remote data the function for tv.dataItems() show nothing. How can i access the data from the hierarchical data for my treeview? i want to get all the id for the nodes of the treeview.

JavaScript for accessing the dataItem

    var values = ["LA1","LA6","LA12"]; 


    var setTreeViewValues = function(values) {
    var tv = $("#AccountingTree").data("kendoTreeView");

    document.write(JSON.stringify(tv));

    tv.dataItems().forEach(function(dataItem) {   
    alert("test");
       if (dataItem.hasChildren) {
       var childItems = dataItem.children.data();
       //document.write(JSON.stringify(childItems[0].items[0].programID)); 
    }

   // document.write(JSON.stringify(dataItem.items)); 
      if (values.indexOf(childItems[0].items[0].programID) > -1) { 

        dataItem.set("checked", true);
      }
    });


  };

  setTreeViewValues(values);

The output is here

Is there anyone know what the problem happen here?