How to control an ATI amp

I have a Bel Canto Pre2P which has 2 stereo outs. Both pairs of outs operate simultaneously with no opportunity to adjust. I have 1 set of output running into an active crossover network which then feeds 8 of the 12 channels in the ATI. I would like to use 2 of the last 4 channels for a HT setup feeding a signal from the second pair of Bel Canto outs.
The ATI allows each channel (actually pairs of 2) for a total of ix to be adjusted, either on / off of volume set.
In order to do this i need to connect a plug to a "phoenix" 3 pin sockets (each socket control 2 channels). The 3 pins are up , center and down. Apparently by connecting either the up or don pin to the center will turn the channel off.
Has anyone had any experience with this