On page of the HX Stomp manual, under additional controls, you can read:
"Midi cc #:69 Value: 0-2, 8 and 9 Snapshot select (0=Snapshot 1, 1=Snapshot 2, 2=Snapshot 3, 8=Next snapshot, 9=Previous snapshot) "
How can i set a button to scroll from Snapshot 1,2 and 3 and be able to save to the PBC...