Signals & Track Display Of Zs1, Zs7 Or Zs13 On The Main Signal

I would like to have a train arrive on Zs1, Zs7 or Zs13 on certain routes. I haven't found a way to set this yet. Maybe someone can help me.

 

You have to configure the respective route from that signal as a shunt route and potentially add "Zs1", "Zs7" as an entry in the Custom field of the route in the signal's route table

 

I managed to do this for Zs13. Zs1 or Zs7 are somehow not implemented by the signal.