Ship equipment is treated as cosmetic parts by the game, it just defined differently by xml and has an effect applied again by xml. All parts are listed in CosmeticComponentArtDefs.xml (even lasers, hyperdrive, ect). I was just trying to point you at a possible solution. Also they are not under <ArtDefine> but under <ShipComponentArt> instead. (Which you should know already if you did a little investigating).