I also have the Symtec Heated grips however I didn't use the rocker switch provided. I used one purchased at a local Electronics store with a rubber boot for protection, installed an LED to let me know the grips are on, fuse protected and even installed a relay so that when the bike is on (12v from number plate light to coil), power is given to the switch but if the bike is off, the grips wont stay on. This relay is also responsible for the power to my USB ports (for charging music players on the go).
I mounted the switch and LED on the inner black panel on the left hand side of the tank. It's unused space as far as I can tell and perfect for mounting all the bits and pieces. I'll see if I can dig up a photo.