Ok, here is a solution that works 100% of the time for me.
1) Buy an HDMI Detective Plus
This gadget basically gets programmed with your TV's EDID and then fakes your Media Center into thinking the TV is on 24/7. Genius
2) Go the software route
- Harmony Remote (Logitech)
First, you need to ensure that you get the latest Media Center remote configuration file for your Harmony Remote. You can find this device under
Device type: Computer -> Media Center
PC Manufacturer: Microsoft
Model: Windows Media Center SE
and includes the ability to send Media Center keyboard commands such as Win+1, ALT+1 etc
Then you need to configure the Activity for your Media Center "Watch TV" action to include an additional remote command, which is to send Media Center a custom keyboard shortcut. Since I am using Windows 7 I selected Win+1 to launch the first item in my taskbar
Now you need to download HDMIOn.exe and place it somewhere on your Hard Drive and then pin in to the TaskBar in the corresponding location that you are using for the shorcut.
Alternativley you can create a shortcut for HDMIOn.exe and assign a shortcut key like ALT+1 to that shortcut.
Now when you press the Watch TV Activity on your Harmony remote, the HDMIOn.exe app will launch causing your HDMI handshake to get resent.