I had some problems with my setup and the harmony remote control. If I turn my dm800 + AV receiver (Yamaha RX-V463) + Tv (samsung) on I had a disturbing picture and bad sound!
The problem is that you have to change the order of the power on sequence!
What worked for me was TV -> AV receiver -> Dreambox.

Very strange problem!

Another problem, the exit button is not working properly yet..