jqGrid custom radiobutton

HTML

<link rel="stylesheet" href="http://trirand.com/blog/jqgrid/themes/ui.jqgrid.css">
<script src="http://trirand.com/blog/jqgrid/js/i18n/grid.locale-en.js"></script>
<script src="http://trirand.com/blog/jqgrid/js/jquery.jqGrid.min.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.14/themes/base/jquery-ui.css">
<div style="min-width:710px">
<table id="preclosing">
</table>
<div id="preclosingpagerdiv"></div>
</div>
<input type="button" id="updatebtn" value="Update">
    <div id="preclosingsuccess" class="successmsgdiv">
        Successfully updated.
    </div>

CSS

.successmsgdiv
{
	color:Green;
	display:none;
	font-size:small;
}

JavaScript

var data = {"DOCS": [
        {"ConfigId":1,"Documents":"A", "DocsReceived":true, "Comments":"", "NA":"", "DocGroup":"Maine"},
        {"ConfigId":2, "Documents":"B", "DocsReceived":true, "Comments":"", "NA":"N", "DocGroup":"NewJersey"},
        {"ConfigId":3, "Documents":"C", "DocsReceived":true, "Comments":"", "NA":"R", "DocGroup":"Maine"},
        {"ConfigId":4, "Documents":"G", "DocsReceived":true, "Comments":"", "NA":"R", "DocGroup":"Virginia"},
        {"ConfigId":5, "Documents":"G", "DocsReceived":true, "Comments":"", "NA":"R", "DocGroup":"Alabama"},
        {"ConfigId":6, "Documents":"D", "DocsReceived":true, "Comments":"", "NA":"R", "DocGroup":""},
        {"ConfigId":7, "Documents":"Q", "DocsReceived":true, "Comments":"", "NA":"R", "DocGroup":""}
    ]},
    previouslyselectedRow;

$.extend($.fn.fmatter, {
    dynamicText: function (cellvalue, options, rowObject) {
        if (cellvalue == 'R') {
            return 'Received';
        } else if (cellvalue == 'N') {
            return 'NA';
        } else {
            return '';
        }
    }
});
$.extend($.fn.fmatter.dynamicText, {
    unformat: function (cellValue, options, elem) {
        debugger;
        var text = $(elem).text();
        return text === '&nbsp;' ? '' : text;
    }
});

$('#preclosing').jqGrid({
    datatype: 'local',
    data: data.DOCS,
    colNames: ['', 'Documents Received', 'Comments', 'NA', 'DocGroup'],
    colModel: [
        { name: 'Documents', index: 'Documents', align: 'left', sortable: false, editable: false, width: 20 },
        { name: 'DocsReceived', index: 'DocsReceived', align: 'center', sortable: false, editable: true, edittype: 'checkbox', editoptions: { value: "True:False" }, formatter: "checkbox", width: 140 },
        { name: 'Comments', index: 'Comments', align: 'center', sortable: false, editable: true, edittype: "textarea", editoptions: { rows: "3", cols: "16" }, width: 180 },
        { name: 'NA', index: 'NA', editable: true, formatter: 'dynamicText',...