My is connected to a 5.1 receiver, this one to be exact: http://www.lg.com/ca_en/home-theater-systems/lg-BH7530TB I test out all 6 speakers already with a DVD so I know the receiver and speakers are intact.I do not have the MS WDA but Miracast is built into my Panasaonic tv and I can get up to 7.1 discrete channels, (although my system is set up for 5.1ch). Is your tv connected to your receiver via HDMI? The tv audio output on its own will usually downmix to 2.0ch or 2.1ch
Here's some screenshot from device manager: