Taking the Vault 111 Suit - Clean (ID: 000976B7) as an example: MO2S and MO4S replace the item texture that you see when you drop or inspect the item. http://i.imgur.com/6nw2WjL.png The Armor item is linked to an Armor Addon item here: http://i.imgur.com/HLjGtkR.png The Armor Addon (ID 000976B6) contains a material swap reference for third and first person views: http://i.imgur.com/vYzPR8h.png Looking at the Male Model Material Swap (ID: 000976B1) you see that it specifies the base material (exactly as it is listed in the object NIF) and the swap material. http://i.imgur.com/3mkTIQV.png Be very careful about the paths. You also need to make sure you are pointing to a new BGSM file in your materials folder that points to the desired DDS files in the textures folder. For example, I'm finishing up a mod that adds 7 unique vault suits, each with different textures and attributes. So my ESP has 7 Armor Addon entries, 7 Armor entries, 7 Material Swap entries, and 7 Constructible Object entries. I also have to include the appropriate BGSM an DDS files to place in the \Data\ folder.