Hello epimienta,

Here is one way to do that: 

 <script type="text/javascript">
function UltraWebGrid1_AfterCellUpdateHandler(gridName, cellId){

         //Add code to handle your event here.

   var grid = igtbl_getGridById(gridName);
   grid.Events.AfterEnterEditMode[0] ="AfterEnterEditModeHandler";

          debugger;

        }


    function AfterEnterEditModeHandler(gridName,cellId) {

            alert('Hi From  dynamic added handler');    

}

</script>

Hope this helps