I am trying to use the VPT24-1P to replace an existing 3-way switch. My existing switch, and the mate, are both 3-way toggle switches. They have a Red, Black, Green and White connected to them, with a separate black & white line power in the box. I tried to connect the VPT24 as shown in Step 4B &4C and I get no power to the LED. Then I even tried 4A, and nothing. So for this to work as a 3-way, is the VP0SR REQUIRED?