Thank you Markus!
Now I understand: I always thought a bank = soundbank = category, but a bank is the whole state of all the presets. Got it now!
What I did wrong was to select the "Reserved" category as target for my own sounds. I can load sounds into "Reserved" but when I save the bank, the "Reserved" slots don't remember the presets (I guess because they are reserved(!) for expansions).
I don't know if it is possible to add one or two (or three) User-assignable categories in a further update. This way I could keep all the factory presets plus some of my own sounds.
Anyway, thank you for clarification, I now understand the patch/bank handling!
Cheers
Dumbo