I'm honestly not 100% sure how vtec switches are wired, but I think it is wired to either the vtec solenoid, or the oil pressure switch. In any case, you have to trace the switch back to the main harness, snip or remove it, and rewire the harness together.
Try the easy thing 1st-just unplug the switch and see if vtec still engages at 5k rpms.