Ok, done!
I have adopted the note solution instead of sysex. I use Ableton. Two solutions on midi control:
1) use the midi clip to send bank=1; sub= n it depends which registration you would like to use. In the same folder you need to put all registration bank; pgm =depends which registration number bank you would like select.
2) use a max4live module named "Programchanger.amxd" (
https://maxforlive.com/library/device/4051/program-changer): MSB=1; LSB=n depends which registration you would like to use. In the same folder you need to put all registration bank; Program Change: depends which registration number bank you would like select.
On Ableton, send midi to psr975 usb2 ch 1
On PSR, set up MIDI USB2 to receive on USB 2, track 1, "Keyboard".
What purpose does it serve?
If you want to program some ableton scenes to send the registration and the bank number stored within the registraton this allows you to automate the style, voices, volumes etc. It is not a small thing!
Many thanks