jQuery Grid Plugin - jqGrid

Hi,

I have implemented Jqgrid search on sinlge column using below code. I have a textbox,when i enter some text and click on a button it will filter the data on JqGrid. Here i am doing search on Name column.

 $('#btnSearchAssociatedClients').click(function() {
        var grid = $('#tblAssociateClientSummary');
        var relatedClientName = $('#txtRelatedClientName').val();
        var postdata = grid.jqGrid('getGridParam', 'postData');
        // build up the filter
        // ['equal','not equal', 'less', 'less or equal','greater','greater or equal', 'begins with','does not begin with','is in','is not in','ends with','does not end with','contains','does not contain']
        // ['eq','ne','lt','le','gt','ge','bw','bn','in','ni','ew','en','cn','nc']
        var myfilter = { groupOp: "OR", rules: [] };
        myfilter.rules.push({ field: "Name", op: "cn", data: relatedClientName });

        $.extend(postdata, { filters: myfilter });
        grid.jqGrid('setGridParam', { search: relatedClientName.length > 1, postData: postdata });
        grid.trigger("reloadGrid", [{ page: 1 }]);
    });

In the code the Name column is using below formatter so it will combine first name and last name.

var nameFormatter = function(cellValue, options, rowData) {
    return rowData.FirstName+" "+rowData.LastName;
};

Note:- The data also contains Name column which has different data.

My problem is the search is working on Name column data, not on the displayed data.. Please provide me the solution how to implement search on formatted data.