jQuery Grid Plugin - jqGrid

Hi everyone.

In my grid i have a col formated by me that shows an input type radio, what i want is when a check the radio, the row get selected.

this is my code:

in the grid colModel:

{name:'opcion', width:35, align:'center', formatter: myFunction},

after the grid declaration:

function myFunction(cellvalue, options, rowObject)
{
    seleccionar = '<input type="radio" id="'+options.rowId+'" name="seleccion" onclick=" javascript: enviar('+ options.rowId +')">';
    return  seleccionar
}

function enviar(param)
{
    $('#grid_bonificacion').setSelection(param);
    ... some

        code

        here ...
}

the problem is it works only the first time i call it, and not properly at all because inspecting with firebug it shows something like this: $t.p.selrow.replace is not a function

of course if i call it again the row does't get selected.

would appreciate any help.

thx.