You don't connect the TV to the AV receiver. Connect both the cable box and DVD player with separate L/R audio cable to whichever 2 inputs you prefer (Video 1 and 2 are the most obvious). Connect both to the TV with HDMI.
Sorry if I seem a bit dense, but let me get this straight...
I currently have hdmi from tv to cable box.
I need to plug the red/white into the cable box and AV receiver.
That way the video flows from cable box to tv via hdmi and the audio flows from cable box to AV receiver via Red/White audio cable?