Multiplayer Custom COOPS Client problems

[MegOhm]

A friend in our group wrote a Custom MP Coop mission for us. We placed it in both the Steam and Softclub coop folders. It shows up in the Sim and the Host can get in a plane and fly but the Clients cannot get in a plane and do not have a fly buton. The mission runs great, it's just the client side.

Does anyone know for sure if MP Coop currently works and what folders the mission files should be placed in?

Any tips out there or is it just not ready? The existing coop mission and the Dogfights missions do work but are kinda porked.

He tried reverse engineering the COOP but it didn't help.