Thank you Lee,
my system is more complex , because it has two operation modes :
audio or video
In audio mode C 4000 is the master preamp while in video mode Yamaha DSP E 492
becomes the master preamp .
Yamaha DSP E 492 is an AV amp with only 3 power amps ( center and rear speakers only )
I have connected Yamaha's front outputs into the external processor input of C4000
I have also used two external relays powered by Yamaha AC switched outlet to operate
external processor input and to switch the rear speakers from C4000 to Yamaha .
In this way with only one remote control I'm able to command :
-C4000 + M400s power on/off
-Yamaha ( volume , inputs ,Dolby modes , etc .
-Tv
-Vcr
-Blue ray player
-Dtt decoder
-Satellite decoder
-Living room lights .
Ciao
Marco
PS: my remote is very cheap ( 29€ only ) , but it has the " learn function ".
It's Meliconi Digital 6 ( an italian brand )