outlaw 950 setup

I just got a used outlaw 950. I have 6 speakers in the room, and 6 channel amp. The outlaw manual calls for 7 speaker setup. In the onscreen menu and under speaker setup I set my R&L rears as the surround and R&L rears to a single speaker (LB/RB). I can't figure out where to connect the RCA jack for the rear center on the 950. In other words the rears are left and right rear or 2 connections but with a single speaker at rear center which connections maps to this?
Any help would be appreciated.
Thanks