Hi *I* (hope you don't mind - it's less typing!)
Do you have to use SX at all?
See if you can use MIDIOX.
You 'should' be able to just run MIDIOX (with no DAW running) and it will capture the MIDI-In. (once you've told it which MIDI ports to listen on).
Xenakios, of course, you are quite right - it would be
much easier for Houston owner to test/debug.
Edit: Are the faders motorised?