Glackowitz / brandenpro, I tested both set of codes above and here's my results: They both are discrete sets, however, if the power button on the Xbox is pressed between these commands, without anything else being pressed, the Xbox will ignore the next issue of the same command.
For example: If the xbox was turned off with the PowerOff command, then turned on with the PowerOn command, then manually turned off at the front panel, the xbox will ignore the PowerOn command, until another command is sent. Even though it is off at this point, another command flips a toggle and allows the PowerOn command to get through. The same is true in reverse with PowerOff command and a manual turn on. This happened with both sets of codes above.
Now this got me thinking, so I grabbed the Xbox remote (Joytech) that I think came with a cable I bought (I don't have the HD-DVD add-on), and learned a few commands twice through the IR-PRO, and sure enough, each one had two different hex codes from successive learns.
So this remote has a "#" button, which I have no idea whether it does anything to the normal xbox operation, but I used it's code set in different combinations with the discrete power commands, and was able to form two macros that performed without fail as discrete power commands. I tried repeated tests of manual power presses and different commands, and couldn't trip them up.
I know it's not the perfect single discrete command, but here it is:
