Thanos - Take a look at Bob Tavis's diorama "Brave Little Belgium" for inspiration and info.
If your question is did the Uhlan trousers have a leather section, I don't believe they did, but don't take my word for it.
You could ask this question of the uniform experts on the Great War Forum web site. Those guys know the answer! Just type Great War Forum on your browser and you'll find it pretty easily.
All the best,
Dan