I have a mitsu WD-65731 and am using JVC RX-D206B receiver. I have a HDMI XBox 360 connected to the television and a digital coaxial cable from the tele to the receiver. for some reason the receiver isn't auto detecting a digital audio siginal so i can't get dolby digital. when i switch to component cable for the xbox and use the optical cable directly from the xbox to the receiver everything works as it should. what do i need to do so i can use the hdmi from the xbox to the tv and digital coaxial to the receiver and still get a dolby digital signal?