I posted this a long time ago but the question has arisen again recently. This is what I use for proper start up using my Harmony H900 and never have HDCP/EDID/HDMI handshake issues. This solution is free (besides the cost of the remote, I guess) and works for me by YMMV.
What this does is give time for HDMI sync to occur with a couple 5 second remote pauses and closes WMC (alt F4) and then loads it again in LiveTV. This replicates what I've been doing manually, (although I minimize/maximize WMC and this closes it and opens it.[/quote]
Since I originally posted this, I changed the Media Center PC2 to go to the MCE Startpage instead of the desktop because if Windows Media Center was not already open, Alt F4 brings a pop up to shut down the computer. I also shortened the pauses to 1000 milliseconds (1 second) too. Although the original sequence was working, this new sequence is a bit faster and removes the possibility that the computer will shut down when starting the Activity. Not that it won't due to some other reason but at least not due to the start up sequence programmed into the Hed into the H 900.
Other than that this start up sequence is working well.