Hi Nick
Thank you very much for your answer :)
PF did change my Hash seed and nw it only contains 2 special chars {' so far so good...
I have directly added the Hash to /includes/modules/payment/postfinance.php which unfortunately didnt solve the problem.
But both times I did get the same hash in the hidden field.
022d44c0270e2092d6f5c900e697e700
022d44c0270e2092d6f5c900e697e700
Im not sure if I did understand the bit with the md5 generator:
I did convert the master shop id XXXX_yp, the Hash, the shop id XXXX and the currency CHF in the md5 generator.
So I have 4 md5 generared strings. But what am I doing now?
Thanks for your help
Brigitte