Can't texture first test part properly

[Pacca]

I'm trying to create a part based on a premade model. The only major change to the model was that it was scaled down in Blender to match KSPs' scale. I did a lot of reading and searching, and seem to have the vast majority of the work done. The part appears in game with the correct model, hitbox, and test stats (cfg copied from the atmosphere sensor, currently unchanged). The only problem is, it doesn't texture properly at all. It renders just fine in Unity, but renders improperly in game.

I think I've somewhat figured out the problem; the model accepts four different texture files, which map to different sections of the model. I set all four of these properly in Unity, and it looks fine there. But in game, it seems to map the last defined texture in the list to the entire model! I replaced the last texture with "none" to be certain, and sure enough, the entirely model was re-textured to an off white color in game. I tried looking for questions that related to this problem, but I didn't find anything helpful.

Does KSP support this, and I'm just doing it wrong? Do I have to jump through loop holes to make it work? Or am I approaching this entirely wrong? Keep in mind, this is my first attempt at modding KSP. I apologize if I'm not providing enough info; feel free to tell me exactly what you need to see and I'll look into adding it.

Edited January 15, 2019 by Pacca
added missing text

[SpannerMonkey(smce)]

Hi you can only  have one material per mesh,  theres no way( i know of ) to get more than one without having individual mesh objects each carrying their own material/shader  and texture set .  I'd expect there to be a warning in the inspector that you have more materials than renderers