combobox in datagrid cellrenderer

Question

Hi all... searched looooong and hard for this without luck:

I need to put a combobox in a column of a datagrid. The user just need to select a value from the existing combox items. I know I need to use a custom cellrenderer. Please see my current attempt below.
This attempt successfully inserts a combobox into the datagrid, BUT without any data in the combobox. In fact, when I click on the combobox in the datagrid, it is the same as a normal combobox on the stage without a dataProvider. In other words, it doesn't even open.

Thus, I need to know how to modify my cellrenderer to correctly add the data to the combo and accept changes made by the user when selecting a value from the combobox.

Any help would be highly appreciated! Please note that I'm using AS3 and not AS2 and not Flex.

package {

import fl.controls.ComboBox; 
import fl.controls.listClasses.ICellRenderer; 
import fl.controls.listClasses.ListData; 
import flash.events.Event;
import fl.data.DataProvider;

public class ComboBoxCell extends ComboBox implements ICellRenderer { 
    private var _listData:ListData; 
    private var _data:Object; 
    private var _selected:Boolean;
    private var _mycombo:ComboBox = new ComboBox();

    public function ComboBoxCell() { 

        _mycombo.addItem( { label:"MasterCard", data:0 } );
        _mycombo.addItem( { label:"Visa", data:1 } );
        _mycombo.addItem( { label:"American Express", data:2 } );
        trace("drawn");
    } 

    public function set data(d:Object):void { 
        _data = d; 
    } 

    public function get data():Object { 

        return _data; 
    } 

    public function set listData(ld:ListData):void { 
        _listData = ld; 
    } 

    public function get listData():ListData { 
        return _listData; 
    } 

    public function setMouseState(state:String):void{
    }

    public function get selected():Boolean{
        return _selected;
    }

    public function set selected(value:Boolean):void{
        _selected = value;
    }
} 

}