Anytime I equip a "heavy" weapon (flamer, plasma caster, rocket launcher) it is invisible in 3rd person when sheathed. Then when I go to use the weapon it suddenly appears in my hands and then vanishes again when put away.

In FO3 those weapons would appear on my character's back like every other weapon, but in NV they just disappear. Is there any way to fix this? I like running around with the flamer's big barrels on my back, it makes me feel like I'm in the Ghostbusters.