ExtJS 4.1 Infinite Grid Scrolling doesnt work with Dynamic store using loadData

I have to load first grid panel on tab and then load data into store using loadData() function which is working fine, but now I have to integrate infinite grid scrolling with it.

Is there any way to integrate infinite scrolling on fly after loadData into store..? I am using ExtJS 4.1. Please help me out. Here I am showing my current script in controller and grip view panel in which I have tried out but not working.

Controller Script as below:

var c = this.getApplication().getController('Main'),
    data = c.generateReportGridConfiguration(response,true),
    tabParams = {
        title: 'Generated Report', 
        closable: true, 
        iconCls: 'view', 
        widget: 'generatedReportGrid', 
        layout: 'fit', 
        gridConfig: data
    },
    generatedReportGrid = this.addTab(tabParams);

generatedReportGrid.getStore().loadData(data.data);

On Above script, once I get Ajax call response, adding grid panel with tabParams and passed data with gridConfig param which will be set fields and columns for grid and then last statement supply grid data to grid. I have tried out grid panel settings by following reference example: http://dev.sencha.com/deploy/ext-4.0.1/examples/grid/infinite-scroll.html

On above page, Included script => http://dev.sencha.com/deploy/ext-4.0.1/examples/grid/infinite-scroll.js

My Grid Panel Script as below:

    Ext.define('ReportsBuilder.view.GeneratedReportGrid', {
    extend: 'Ext.grid.Panel',
    alias: 'widget.generatedReportGrid',
     requires: [
        'ReportsBuilder.view.GenerateViewToolbar',
        'Ext.grid.*',
        'Ext.data.*',
        'Ext.util.*',
        'Ext.grid.PagingScroller',
        'Ext.grid.RowNumberer