Ok done...And do I ever feel icky after playing that mess for 20 minutes.
From the looks of things it can't be done.
When you shoot a rocket the launcher stays the same with a rocket loaded. When you reload the rocket just magically drops away during the animation and a new one is put in. Not until you are completely out of ammo does it look like the picture below.
So yeah it either can't be done or the makers of special forces are the most lazy/dense bunch in the world.