jQuery Grid Plugin - jqGrid

I have two fields eventDate and eventTime. On the grid I would like a single "Event Time Stamp" column, but on the add/edit dialog I would like the fields seperated. I set the hidden:true and edithidder:true for the eventTime. I also created a custom formatter for the eventDate field to combine the two on the grid:

      formatter:function(cellvalue, options, rowObject) {
       if (inDialog)
        return cellvalue
       else
        return rowObject[2] + " " + rowObject[3];
      }
     }

inDialog is a boolean is toggle based on beforeShowForm and onClose events. inDialog is setting properly but the default field value for eventDate is "mm/dd/yyyy hh:mmtt", where I want it to be "mm/dd/yyyy".

Any ideas and/or am I going about this the right way?