Here's how to assign a pad to turn the Click On and Off in the SPD-SX:
1. Press MENU.
2. Cursor to "SYS" and then press ENTER.
3. Cursor to "PAD/FS CTRL" and press ENTER.
4. Hit the pad that you want to assign the Click On/Off function to.
5. Press the (-/+) button to select "CLICK" for that pad.
6. Press EXIT when you're finished. The new setting is saved automatically.