jQuery Grid Plugin - jqGrid

I am trying to load the colNames and colModel dynamically. For this I retrieve a string (employeenr|last_name|first_name) by a JQuery AJAX call:

$.ajax({
        type: "GET",
        url: "AjaxData.ashx",
        data: "datatype=employees&what=columnnames",
        success: function(columnNames){
          jQuery("#grdEmployees").jqGrid({
            colNames:columnNames.split('|'),
            [...]

This works fine for the colNames property, but I can't figure out how to load colModel dynamically, since this is a multi-dimensional array and simply splitting on a single character like I do with colNames, doesn't work:

name:'employeenr', index:'employeenr', width:100, editable: true, edittype: 'text', editoptions: {size:6, maxlength:6}|

name:'last_name', index:'last_name', width:100, editable: true, edittype: 'text', editoptions: {size:6, maxlength:6}|

name:'first_name', index:'first_name', width:100, editable: true, edittype: 'text', editoptions: {size:6, maxlength:6}

Does anyone have a clue how I should dynamically load colNames and colModel?