Force Radeon 5670 output signal to HDMI port

I used connecting the HDMI output to my TV as second display to watch movie that I save on my PC. However, recently that TV cannot be detected by my PC which use Radeon 5670 as graphics card. After detail checking and test, I found it was my TV's HDCP chip has problem which cannot send the EDID information to Radeon. So I wonder if there is any way I can force Radeon output signal to its HDMI port even it doesn't detect a connected display?

I found there is way to do this for nVidia card by changing the registry:
http://www.gamesdust.nl/index.php?id=247
So I hope there is also have a similar way for AMD.