KarlKlammer
Thanks for confirming it! It was reported in this issue that it was not even working with secure app spawning OFF for some time. Since no one had said otherwise, it seems it has been deemed around here not to work at all any more.
A week after your reply, Postfinance released a new beta (6.1.0). It is currently working with secure app spawning ON. It is, however, very slow, but it’s probably for another reason.