To the OS and software, Pisound’s MIDI ports appear the same as USB MIDI ports. Patchbox OS has our own amidiauto background process, some details about it can be found here. It should automatically take care of making virtual MIDI connections between the hardware ports, and software ports (such as ORAC), when devices get connected.
If MIDI does not seem to be flowing in the expected way, you can take a look into the virtual MIDI connections by running:
aconnect -l
Feel free to share the output here, after you have connected everything you want to use.