Adding a Weapon in a holster on an Armor

[Crabbi]

Hi there,

 

I haven't had much luck in adding a weapon for a holster via Blender, when I render the model, the weapon will not show up in the geck / in game. The weapon models from other mods that have attached weapons to the armor such as those from Nivea's Spice of Life (http://newvegas.nexusmods.com/mods/44476/?)

 

any ideas?