I have just purchased the new 360 slim. I am connecting the HDMI to the TV for video and i have an optical cable from the optical out on the 360 going to my 5.1 amp. The issue is that the audio is going to both the TV via the HDMI and the amp via the optical cable. I just cant find a setting anywhere on the 360 to tell it to output to one or the other. How can i stop it from outputting the audio via the HDMI when i have my 5.1 amp on?