How to add total row at the bottom of a w2ui grid?

$('#grid').w2grid({
    name    : 'grid',
    columns: [               
        { field: 'recid', caption: 'ID', size: '50px' },
        { field: 'lname', caption: 'Last Name', size: '30%' },
        { field: 'fname', caption: 'First Name', size: '30%' },
        { field: 'email', caption: 'Email', size: '40%' },
        { field: 'sdate', caption: 'Start Date', size: '120px' },
        { field: 'sdate', caption: 'End Date', size: '120px' }
    ],
    records: [
        { recid: 1, fname: 'John', lname: 'doe', email: 'vitali@gmail.com', sdate: '1/3/2012' },
        { recid: 2, fname: 'Stuart', lname: 'Motzart', email: 'jdoe@gmail.com', sdate: '2/4/2012' },
        { recid: 3, fname: 'Jin', lname: 'Franson', email: 'jdoe@gmail.com', sdate: '4/23/2012' },
        { recid: 4, fname: 'Susan', lname: 'Ottie', email: 'jdoe@gmail.com', sdate: '5/3/2012' },
        { recid: 5, fname: 'Kelly', lname: 'Silver', email: 'jdoe@gmail.com', sdate: '4/3/2012' },
        { recid: 6, fname: 'Francis', lname: 'Gatos', email: 'vitali@gmail.com', sdate: '2/5/2012' }
    ],
    summary: [
        { recid: 10, fname: 'John', lname: 'doe', email: 'vitali@gmail.com', sdate: '1/3/2012' }
    ]
});


Source: http://w2ui.com/web/docs/1.5/w2grid.summary