jQuery Grid Plugin - jqGrid

I have defined a datagrid in the following way:

$("#grid").jqGrid(
        {
            height: 400,
            autowidth: true,
            datatype: 'local',
            altRows: true,
            colNames:
            [
                'col 1',
                'col 2',
                'col 3',
                'col 4',
                'col 5'
            ],
            colModel:
            [
                { name: 'col1', index: 'col1'},
                { name: 'col2', index: 'col2' },
                { name: 'col3', index: 'col3'},
                { name: 'col4', index: 'col4', formatter: cellFormatter},
                { name: 'col5', index: 'col5', formatter: cellFormatter }
            ],
            rowNum: gridData.rows.length,
            viewrecords: true,
            recordtext: "{2} Results",
            sortname: 'col1',
            sortorder: "ASC",
            caption: "caption",
            pager: '#pager',
            pgbuttons: false,
            pginput: false
        });
        $("#grid")[0].addJSONData(gridData);

the idea is that i want to send the data down from the server as gridData with the original request.

when the above code runs, it generates blank rows for each record, the ones with cell formatters will input undefined.

I do not want to use array data because i do not want generically assigned id'.  I need to minipulate the data base on outside criteria so i need non generic id's.

if i change the datatype to json, it does an ajax request for the data after the page loads which is unnecessary for this particular grid.

if i change the datatype to function(postData){}, it works and makes no request, however the sorting then no longer works.