As you mention, it's a heraldic shield, so they don't have a faction- or bannerspecific texture on them. That is getting done via some codelines which reference to the banners of the mod. You have to watch out for the item entries as well.Hello again Fladin.
I have now a problem with transferring one of your heraldic shields to another mod.
I pasted the textures of the meshes both in Openbfr and on the textures file.
However, the shield appears improperly in the game. It's like various textures mashed together with the heraldic part being a small part of it.
It's this one :