Addition: After the part a few days lying around (and I was too lazy to return it) and its practical uselessness had demonstrated impressively in a few more attempts, I finally step to help themselves. The problem actually comes from the fact that the Chinese have (or Indians) simply adopted the case for the normal S 4 (without hardware keys), wherein the leather case for lack of capacitive characteristics can press nothing for Activa.
I have now simply enlarged the opening for the USB port. That just goes with piercing or punch. Chisel was just not at hand, but a 16-mm-punch. Thus the cut-out has been increased to about 30 mm x 30 mm. An appropriately sized hole iron would have made it a bit easier, but it went well. The small inaccuracies in the outline were then removed with a cutter (on Proxxon or Drehmel-Bohrschleifer); Use a file and sandpaper that would be gone. Result: Home button is released, it expresses nothing more and nothing turns unintentionally one (and the device looks to the shell like a dork phone).
Addendum after six months usage: The shell has decomposed, plastic mount for the phone was only cracks, then broke away parts. Starting with damage.