Innovator,
If I'm interpreting your post correctly, you cannot disable the center channel when using stereo 5 or stereo 7 modes. See the following thread for more info:
http://ubb.outlawaudio.com/ubb/Forum15/HTML/001081.html
Unfortunately, even if you had a monoblock amp with a power switch that still wouldn't do the trick for you because the front left and right channels wouldn't sound correct (the common signal intended for the center channel has been removed in processing). The center channel has to be disabled in the processing not at the speaker or amplifier.
Isn't it ironic that I can't get stereo 5 or 7 to operate because I don't have a center channel and you don't like stereo 5 because you can't disable the center channel in this mode! I wonder if anyone at Outlaw headquarters is paying attention to this?

------------------
Tekdredger