Remove the seat and you'll see the solenoid back by the battery. Remove the solenoid cover and unplug the white multipin solenoid terminal.

NOTE - On this model bike Ducati supplies 12 to the rest of the loom through one of the pins on this connector. When you put the bike back together you will have a dead system until you replace this plug. This is different from other Ducatis that get the 12V from another connection on the bike.