If you have factory reset the unit then all your programmed settings would have been lost.
I'm not familiar with your amp and it's settings sorry, but you can download them and have a read through the speaker setup section.
I would assume you will need to select 7.1 and either enable atmos or bi amp the rear pair of channels to front and use them for the up firing speakers.
I'm doing similar with my old Sony amp to give me a pair of overheads (post further down the page)
