OK here is what is happening for me...
When i take a already existing (example) eye glasses or head ware and give them a new ID to create my own with specific enchantments, they end up on the side of the head in-game??
How can that happen when i use the same mesh and everything else isn't changed for the item except ID and enchantment???
You have to go to Character>Update FeceGen model availability, but if I'm not mistaken doing so introduces yet another problem by the NV Geck, and I think it causes ALL headwear in the game to now be sideways. So, you now have to edit something via FNVedit that I'm not sure how to do. I think I read somewhere on here that some gracious folks are working up some tutorials on how to do this in FNVedit but I could be mistaken. Sorry that's not much help but it's a start.