what kind of track are you using? If it's tubular with METAL ties there's a simple answer because I do it. Buy or make you own insulated track. Put that piece directly touching the switch tracks with the insulated section on the SAME SIDE as the switch's "derailer" track. Do that for the pass thru and the curved parts of the switch.
Use 3 metal pins to connect the insulated track to the switch but use a dummy pin on the other side of the insulated track on the insulated section of that piece of track. What you are doing in effect is extending the 3 rails of the switch and pretending that the insulated track piece is part of the switch.
No extra wiring is needed. When your engine makes contact with the insulated rail, the metal ties make the connection that your rubber tired engine can't make.
I hope I was clear enough. It's really simple to do.
I wish I knew of a way to draw a simple diagram because what I wrote might sound hard but it isn't hard in the least.
- walt