Hi,
thanks for the hint. I tried the sms and call demos and they work. 
So it seems that somehow the more complex demo from the create kit is not working for me and my test with the low level functions does also not work. But the two simple demos work. Maybe i can’t just call the low level functions the way i do. 
But now i have a starting point from where i can go on and find the correct way to use these functions.
Ciao,
Rainer