I dont know if its possible but the idea is to use the weapon slots (hotkeys) in order to make weapons appear on your character.
So slot 1 is the default slot that shows ur primary weapon that is equipped by default,
slot 2 is the ammo slot so dont think that one can be used, slot 3 might be used for a rifle, this only shows up on your character but is not used as the primary weapon
maybe its even possible to use more slots to show melee weapons too
I am clueless if this is possible as im a noob with the GECK and all, but I think the game should have had this from the start
Another thing id like to see are holsters for the weapons, same way Oblivion handled the scabbard for swords
I can model/texture the holsters if anyone tries to take up this request