I believe the Collosus only does HDMI input from devices that don't use and HDCP like an xbox.
The Directv receivers definately use some copy protections on the HDMI output, which is probably why you have to reboot to get it to work. Honestly I wouldn't have expected it to work at all.
I have the USB Hauppauge that precedded the Collosus, and it only uses the component video / optical audio, but it works great to record HD programming to DVD or Bluray. You may end up using component.