Custom textured UAV backpack resetting once disassembled

[felipechapmanfromm 5]

I have retextured a UAV backpack and it is all working great, apart from the fact that when you assemble then disassemble the drone, the backpack texture changes back to the original IDAP texture.

 

The two questions I have are:

1. How do I prevent this from happening?
2. Is there a way to texture the assembled drone, so it has a custom texture once assembled out of that specific backpack?

 

Any responses are appreciated.

Cheers