[ExtJs] dynamically Add button PagingToolBar

==== create PagingToolbar ====
var toolBar = new Ext.PagingToolbar({
pageSize:10,
store:store,
displayInfo:true,
displayMsg: 'total{2} {0} - {1}',
emptyMsg:'no data'
})

======== create Toolbar Button =======
var sbun = new Ext.Toolbar.Button({
pressed: true,
enableToggle: false,
text: 'Create',
id: 'createId',
cls: ''
})


======= create Grid with PagingToolbar =======
var grid = new Ext.grid.GridPanel({
el:'Firmware-grid',
store:store,
cm:cm,
//sm: new Ext.grid.RowSelectionModel({selectRow:Ext.emptyFn}),
viewConfig:{
forceFit:true
},
title:' grid title',
width:500,
height:500,
loadMask:true,
frame:false,
bbar:toolBar
});

====== Add Toolbar Button ====
grid.render();
grid.getBottomToolbar().add('-',sbun);