Issues editing meshes (especially textures) in Skyrim

[numberland]

I've had real issues where I have edited a mesh for skyrim, the mesh loads fine but I cannot create a new texture. I'm generally taking part of a mesh (either one whole NiTriShape from a mesh that included one or a mesh that I have editted to cut down in blender). I can get the mesh to work fine, but (in most cases) I cannot get the texture to work. For instance I want to add a mesh based on a skyrim inn sign where I am taking just the sign itself and throwing away the part of the mesh that is the post and add it as a building option for the Hearthfire houses. I can seem to get this to work for some vanilla items but I need to create at type suitable for the building script to accept (it doesn't seem to like signs), so really I want to create an entire new object with suitable textures. Anothe example is to use part of plants or ingredients to take into harvestables. In all of these cases textures just don't show up whatever I do. I've got a couple more places to look but I've been googling lots, have gone through the Creation Kit tutorial on exporting meshes and no joy.

 

Any pointers would be appreciated, links would be awesome (though not for simple retexturing because that I can do absolutely fine)... um, help?