hey bro
i had the same thing. make sure you follow ALL THREE of these steps and let me know if you're still having problems:
1) The SKY HD box does not output multi channel through the HDMI. An optical digital cable needs to be used as well as the HDMI connection.
2) In order to get surround sound from SKY HD you will need to assign both the HDMI and optical connection to a particular input of the AV receiver. eg TV/SAT (not from HDMI 1,2,,3 etc). To do this firstly switch off KURO link and then from the receivers Input assignment menu, select TV/SAT and designate which HDMI input and Optical connection you wish to use.
3) Then use the Signal Select button to select Digital (NOT automatic or HDMI).
NB: Please note not all SKY HD channels broadcast in 5.1 all the time.