Can Item objects be mounted to another object?

I asked this in another thread, but no one has answered. So I have to ask again.

Can an Item be mounted to another object, say, a vehicle? I manage to mount a staticShape object to the vehicle, but when I try to mount an item to the vehicle, the item doesn't appear. What might be the problem?

Here is the code.

%device = new StaticShape() {
dataBlock = device1;
};

%Field= new Item(){
dataBlock = Negative_Field;
};
%vehicle.mountObject(%device,1);
%device.mountObject(%Field, 0);

As a result, the StaticShape object %device appears on the vehicle, but the Item object %Field doesn't appear.