run the front left and right speaker outputs from the processor to the 2-channel preamp's "video" or "aux" input. then connect your cd player, turntable, etc to the 2 channel pre and your HT stuff to the processor and then choose a spot for the 2 channel pre to stay, volume control wise, and match the processor levels for the center and surrounds around that. that way, whenever you watch movies or whatever, you just set the volume control on the 2 channel, turn it to "video" or "aux" or whatever, and it plays through. this is the only way you can have the maximum fidelity of your audio components and can use your processor through it without swapping out cables.
if this is confusing, look at my system. it's explained in more detail.
if this is confusing, look at my system. it's explained in more detail.