Help Relation Of 3 Model

Model 1
============
cargo_loader
============
loader_id
loader_name
loader_price

#cargo_loader has many cargo_details

Model 2
============
cargo_details
============
cargo_id
cargo_total
loader_id


#cargo_detailshas many cargo_items

Model 3
============
cargo_items
============
cargo_id
cargo_length
cargo_width
cargo_height
cargo_actualWeight

/************** My Problem ***********************/

i want to view in the cgridview


[cargo_items->cargo_actualWeight] in my cgrid view, but my cgridview provider from "cargo_loader" model

heres my relation of my model "cargo_loader"

public function relations()
	{
		
            'cd' => array(self::HAS_MANY,'Cargo_details',array('loader_awb'=>'cargo_id'),'through'=>'dim'),
            'ic'=>array(
                        self::HAS_MANY,'cargoitems',array('cargo_id'=>'cargo_id'),'through'=>'cd'
                       ),
                  
              
                    
		);
	}

my cgridview

$this->widget('bootstrap.widgets.TbGridView',array(
	'id'=>'sea-sales-monitoring-grid',
        'type'=>'striped bordered condensed',
	'dataProvider'=>$model->salesReport(),
	'columns'=>array(
                array(
                        'filter'=>true,
                        'name'=>'Act Wt',
                        'value'=>'sum($data->ic->cargo_actualWeight)'
                ),

	),
)); 

iwant to get the sum of cargo_actualWeight, and display in cgridview...

thanks in advance