Have you tried finding alterative actions that switch on the machine.

For example. "Play" will usually switch on a DVD player from Stand by.

To use this.

To Switch On.

Alias- "Play"+"Stop" to the Power On button. (if the machine is already "on" it will have no effect.

To Switch Off.

Alias- "Play". Delay. Alias - "Power off". This will put the machine in an "ON" state from any situation and then turn it off.

I found that the Number Keys worked best with my panasonic TV. And this after a lot of messing with much more complicated concepts.