I use a WEMO switch to control power to a 12v relay connected across the remote. Power terminal on my 6700.
My 12V power bus is powered all the time
"The remote on/off works by using the RCA remote-on connector on the back of the radio. Latch the line to ground and the radio will power up, remove ground and the radio will power down. Note that this is a open-collector input so you will need a pull-up resistor or a source that provides a positive voltage on its own."