Target the box with your crosshairs and press the Grab button. On 360 and PS3 press down on right stick, of 'Z' on the PC. Then just backaway from the bench and it will drage them box out where you can get to it.
my idea was to use a gernade and move it by force
Ask Rex to find you loot, he'll fetch it back directly.
^ Rex? In Fallout 3?