Works, with Audio (analog/ADAT) and Midi!!!
Note: While the audio setup works, when using more than 2 channels, one has to explicitly specify "-inchannels 8 -outchannels 8" on the command line to use 8-ch ADAT, otherwise it crashes with segmentation fault.
Hopefully, the screenshot attachment also shows...
IOhannes, thank you for your support!
Wolfgang