I hate to tell you this but the saleperson was mistaken. That particular unit does not have pre amp outs built in to it so you cannot connect an external amplifier. I believe that is possible with the Aventage RX-A830 series on up. If you can or need external amplification I would recommend taking it back and getting an RX-A1030 or look and see it there are any RX-A1020 or -2020 units left from last year. As they are last years model they will be heavily discounted. Hope this helps, and the best way to keep a salesperson straight is to do some thorough research before you start looking, with all the newer stuff coming out a lot of sales people just don't keep up with the technology or what each individual unit is capable of doing. You want to look for a unit that has "Pre Amp" outputs.
Yamaha CX-A5000, ATI AT 2007 Amp (7X200W), ATI AT 2004 Amp (4X200W)Klipsch RF 63's - Main, RB 61's - Front heights, RC-62 - Center, RS-62's - Surround, RS-52's - Rear Surround, 2 Rythmik DS-1510 DIY Subwoofers (With PEQ600XLR3 Amp) each connected with Antimode 8033S-II, Oppo BDP-95, MMF-7.1, Project Phono Box RS, XBox 360, XBox One