jqGrid cómo agregar múltiples casillas de verificación a una columna

I want to add multiple check boxes to a column on edit/add mode. Now this column has a select box with multiple option enabled. I want to replace it with checkbox list or radio button list

My idea is: user should be able to select the relevant options as he desired by checking the check boxes which are listed in a particular cell(on add or edit mode:inline). Once the row is saved should show only the selected option user selected(without check boxes).

Below is my code snippet for the select box for particular column:

{
     name: 'RoomTypes', index: 'RoomTypes', width: 300, editable: true, edittype: 'select',
                   editoptions: {
                         value: roomTypesFormatterEdit,
                         custom_element: function (value, options) {
                             return $.jgrid.createEl.call(this, "select",
                                 $.extend(true, {}, options, { custom_element: null, custom_value: null }),
                                 value);
                         },
                         custom_value: function ($elem, operation, value) {
                             if (operation === "get") {
                                 return $elem.val();
                             }
                         },
                         multiple: true
                     },
                     align: 'left', formatter: roomTypesFormatter
                 },

Where "roomTypesFormatterEdit" return list of hotel room names which will display in select box.

Also I want to re-arrange the height of the editing(edit mode) row to fit with the height of the check boxes or to show all the items in the select box

Please Help Thank you all