jQuery Grid Plugin - jqGrid

I have a column defined as:

{ name: 'cnfamt', index: 'cnfamt', classes:'yellow', align: 'right', sorttype: 'currency',
                formatter: 'currency',
                formatoptions: { decimalSeparator: ".", thousandsSeparator: ",", decimalPlaces: 2, prefix: "$"},
                editable: true,
                editoptions:{
                    beforeSubmitCell : function(rowid,celname,value,iRow,iCol) {
                        alert(rowid + '/' + celname + '/' + value + '/' + iRow + '/' + iCol);
                    }
                }
            }

What I want is that, before the cell value gets posted, I want to add a value into the posted data set. Currently it posts the column name, the value and the row id, but I need to add the record id, which is stored as a value in another column (hidden) of the same row.

So, I hang a fucntion off the beforeSubmitCell event, but it seems to fire at the wrong time. It fires when the cell gets into edit mode, not when the cell is edited by the user and the return key is then pressed. Also, all five parameters come in as undefined in the alert().

Comments?