Mirror's material breaking when editing mesh

[MartyTheGamer]

So I'm trying to flip over the rear view mirror to point towards the right seat and copy or move the left side mirror to the right, where one is missing. Problem is when I import the mesh of the mirror and even simply rotate it in 3DS Max, after I export it and then import it in the game, the entire mirror becomes reflective including the back part, as if it forgets the second material/texture and only applied the mirror one.
So, could anybody help me out with this?