I found a signal when the power is turned on and a signal when the unit goes into a surround mode. I cut the signal path of the rear speakers pre-amp outputs inside the reciever and ran the signals into the NO contacts of a micro relay (dpdt). I then tapped into the signal from the fronts and ran that into the NC contacts of the micro relay and ran the common terminals to the rear preamp outputs. I then took the surround signal and used it to turn the micro relay on so that when the reciever is in a surround mode the rear pre-amp outputs are outputting the rear signal but when the reciever is not in a surround mode then the rear pre-amp outputs are sending a copy of the fronts signal. That gives me 5.1 surround in surround mode and a full four speaker sereo in stereo mode without having to have another pair of speakers.
I then drilled a small hole in the back of the reciever and installed a 2.5mm stereo jack into the hole and ran the signals for power and surround (and ground) to the jack. I made a cord to go from the jack in the back of the reciever to the wall with a opto-isolator chip in line to prevent any noise from coming back into the reciever. In the wall is four 25amp solid state relays to turn on the m-400's which have their own circuit breakers in the panel wired directly to the relays then to four dedicated outlets each with thier own single outlet surge protectors. Three for the front and rears (two fronts are bridged mono and the rear is stereo) and one bridged mono for the center. That way when the reciever is turned on the front and rear amps come on automatically, then when a surround signal is selected, the center comes on automatically.
I am now in the process of using the TEAC reciever's main amp to power speakers in other rooms through two switch boxes (A & B speaker outputs) and a wireless remote control extender so I can control the reciever and cd player from other rooms.
So basically what I have is a state of the art Dolby Digital/DTS surround system with Carver power and clarity for about a quarter the price of a new Sunfire system.