I've pulled the last of my hair out on this..... tried using USB & the midi in/outs fiddling with the midi filter preferences in Cubase...Quick Controls settings... Generic Midi device setup ....@£$%^&*!!!!
Can't even record ribbon controller let alone NRPN parameter changes.
All I can successfully do is keep locking Solaris up with data feedback loops

This works fine on all my other keyboards - some smarty pants must have worked this out?