Download the three STL files and 3D-print two runners and as many hooks as you desire. The runner will fit walls up to 20 mm thick. There is a hook type made to fit to a 30 mm round dowel, and another hook made to fit a rectangular beam (36 x 20 mm).
We recommend 3D-printing these in PLA filament (https://goo.gl/FIwI5t).
Use a saw to cut away a hemisphere of each end of the dowel. Make sure to cut the dowel to the length that fits your shower cabin.
Secure the runners to the dowel by using a short wood screw.