Here are two kit concepts (home and away).
In the center are the three communities (from left to right: flemish, french, and German-speaking).
On the collar and the sleeves, is the national motto "Unity makes strength", in the three national languages (French, Flemish and German). The national coat of arms is in the inside.
For the away kit, I went with black with red accents. The lion from the coat of arms being in the center, and the communities below the crest.
The national motto is in the back, above the name