AAC 5.1 Wanting To Swap Channels

Alright, so this is a tricky one.

I have files encoded with aac 5.1 and 7.1, I have configured ffdshow to encode these streams as spdif to correctly pass thru my tv and then into my soundbar so I have surround sound when I listen to these formats. Great.

However, for some strange reason my soundbar, LG SK9Y, interpets however it encodes those surround files into SIDE surround and not REAR surround. So when ffdshow encodes AAC, and turns it into spdif, to go thru my tv the into my soundbar, I get side firing surround effects instead of rear speaker effects which is what I want.

Is there anyway to tell ffdshow, to swap these channels? I want encoding to continue but side surround and rear surround to be switched.

I have already tried the swap channels option and it doesn't work, I'm assuming because of the spdif encodings. Didn't know if there's another way to possibly change that.

Use a custom mixing matrix on the mixer page in ffdshow. There you can redirect SIDE to BACK.

Or in LAV Audio Decoder, mix to 5.1 and disable the "legacy 5.1" option.