Hi Guys,

iam lookin for a way to control the custom replay cam (ctrl + u) via joystick.

Is there any way or tool?

Emulate the mouse through your joystick's driver. You probably could make a profile only for LFS so it still works well in other games.

Other way might be Insim program, similiar to what LFS TV Director does.
There is a packet to control camera, maybe source of this is helpful: https://www.lfs.net/forum/post/1858791#post1858791