checkbox inside column in listgrid not working

Hi,
I am new to smartclient. I want to create a listgrid with checkbox in column of listgrid so that I can check/uncheck listgrid rows to carry out calculation operations.
I am facing issue as I am not able to show checkbox inside listgrid.
instead of checkbox ‘$63n’ text is appearing as Column header and the rest column is blank.
May i know what is the mistake i am doing?
I am using smartclient 70rc2 version and IE 6 and mozilla firefox3.6.
below is the source code i am writing

<script type="text/javascript" src="resources/js/isomorphic/system/modules/ISC_Core.js"></script>
<script type="text/javascript" src="resources/js/isomorphic/system/modules/ISC_Foundation.js"></script>
<script type="text/javascript" src="resources/js/isomorphic/system/modules/ISC_Containers.js"></script>
<script type="text/javascript" src="resources/js/isomorphic/system/modules/ISC_Grids.js"></script>
</head>
<body>
<script type="text/javascript"> /* <![CDATA[ */
				
				
isc.ListGrid.create({
bodyProperties: { canSelectText:true },
ID:"tradeGrid",
width:"95%",fields:[
{name:"Date", title:"Date"},						 {name:"Quantity", title:"Quantity",type:"integer"},
{name:"Price", title:"Price",type:"integer"},
{name:"type", title:"type",type:"text"}
],
data:[
{Date:"1", Quantity:100, Price:1000,type:"A"},
{Date:"2", Quantity:200, Price:2000,type:"B"},
{Date:"3", Quantity:300, Price:3000,type:"C"}
  ],
		  selectionAppearance:"checkbox",
		   canResizeFields: true,
		    minFieldWidth:"5px",
		    setWrapCells:true,
		    setFixedRecordheights:false,
		    setBaseStyle:"tallCell",
		    canSelectText: true,
		    canGroupBy: false,
		    canSort:false,
		    arrowKeyAction: "focus",
		    fastCellUpdates:true,
		    dataPageSize: 50,
		    alternateRecordStyles:true
				         	}
				        }
				});
			/* ]]> */ 
		</script>

Looks like you’re trying to use some 8.0 features with 7.0. Get 8.0 here: smartclient.com/builds.

Hi,
I wonder what is the smartclient 8 feature I am using in this piece of code?