Date Sorting in a grid

Hi,
I am currently using Date as a string format in my grid, sorting obiously doesn't work as date. Is there any way I can sort this date column as date?
Thanks!

var str = new AW.Formats.String;
    var num = new AW.Formats.Number;
    var dat = new AW.Formats.Date;

    obj.setCellFormat([num,str,str,str,str,dat,num]);
  you have to tell the grid in which column is what kind of data
in this example there is a Date in column-5
then the grid will sort it as a date

and for changing the style of a Date-Object....

date.setTextFormat("mmm d, yyyy");

more under
http://www.activewidgets.com/aw.formats.date/