Using 7 chanel processor with a 5 chanel amp.

I was just forced to upgrade my 5.1 processor to a 7.1 because the old one would not pass HD digital signals.
I still want to keep my 5 chanel amp, as I am in no way interested in 7.1
When hooking up the pre to the amp, should I just leave the two back chanels hanging and just hook up the other 5.
The manual for the new processor didn't say anything about that, it just assumed you are using a 7 chanel amp.
Not sure which prepro you have, but some will allow you to use 2 of the channels for another zone. Either way the answer is yes, you should be able to set it up onscreen for 5 channel.
You should set up the pre/pro to have no surround back channels, making it a 5.1 processor.
Dumb manual. As the other poster says, program the processor to have no surround back channels and don't connect anything to those jacks.

Thanks guys, I will look for that in the programing.