Surround speaker connection question

[freebird]

I'm installing a couple of fxi surround speakers which have to be behind me facing forward, do I connect these to the surround outputs or back surround outputs on my receiver, which is a harmon karmon 254.

[Bernal]

I'm installing a couple of fxi surround speakers which have to be behind me facing forward, do I connect these to the surround outputs or back surround outputs on my receiver, which is a harmon karmon 254.
The user manual found here.
http://www.polkaudio.com/downloads/m...C_FXManual.pdf

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1) DENON AVR-4308CI: Advanced 7.1 CH/5.1+2 CH/ 3.1+2+2 CH A/V Home Theater /MultiMedia Multi-Source/Zone Receiver with Networking and WiFi/170 watts x 7 channels
2) HITACHI P55T501. 55" HD1080 Plasma HDTV
3) DENON DVD-1740: Progressive Scan DVD Video/CD Player
4) DENON DVD-2500BTCI: Blu-ray Disc™ DVD/CD Digital Player/Transport
5) POLKAUDIO LSiC (Center speaker)
6) POLKAUDIO LSi15 LEFT (Front speaker)
7) POLKAUDIO LSi15 RIGHT (Front speaker)
8) POLKAUDIO LSif/x LEFT (Surround speaker)
9) POLKAUDIO LSif/x RIGHT (Surround speaker)
10) SONY SA-WP16 ( Sub Woofer 2X200W)

[VSchneider]

If you are only 5.1, then use surround outputs 1st before back surrounds. I am pretty sure output to back surround will be disabled unless you have side surrounds set.

edit:

my receiver,.. harmon karmon 254.

"harmon karmon" <- waaaaaaaaa :D