Thank you very much, Mark!!
Apparently it's ME who does something wrong, as this one didn't work, either...
Maybe one/more mistakes with my WinUAE configuration and/or wrong hardfile....
I also tried to make a new, empty hardfile from scratch, but it's not even recognized by WinUAE as a proper device...
What can I say? It's not my lucky day and I'm afraid I'll die without being able to see Amax 2.56 in action!
Perhaps it just needs real hardware...