I solved my (lack of attention) problem:
1st day i played with the Be2 plane in training before the front(1915), and it's skin was default Be2 HD (wich got these glassy instruments.
2nd day i started to play on the front with same Be2 plane, but this plane got another skin with an observer in it. This skin does not have the glass-look feature.
So.. all is well, problem solved, sorry to bringing up an non-existing problem.
Either way, thanks for the support!!