Flex ItemRenderer CheckBox

        <mx:DataGrid dataProvider="{usuarios}" width="400">
            <mx:columns>
                <mx:DataGridColumn headerText="Email" dataField="email"/>
                <mx:DataGridColumn headerText="Nome" dataField="nome"/>
                <mx:DataGridColumn headerText="Online" dataField="online">
                                <mx:itemRenderer>
                                    <mx:Component>
                                        <mx:CheckBox click="data.online=!data.online, fnTeste()"  selected="{data.online}">        
 
                                        <mx:Script>
                                            <![CDATA[
                                                import mx.controls.Alert;
 
                                                        private function fnTeste ():void{
                                                            Alert.show("Checkbox clickado!");
                                                        }                                                    
 
                                            ]]>
                                        </mx:Script>  
 
                                        </mx:CheckBox>
 
                                    </mx:Component>                        
                                </mx:itemRenderer>
                </mx:DataGridColumn>
                <mx:DataGridColumn headerText="Online" dataField="online"/>
            </mx:columns>            
        </mx:DataGrid>