5.1 format sound is not output on the DC, how to output it?

Question

Sound cards

Help me please.
There is a DC Philips HTS 3593, sound card Asus Xonar DG.
I bought this card due to the fact that there is Toslink. It seems that everything is connected correctly, but for some reason the DC outputs a pseudo 5.1 sound, the stereo spreads over 6 speakers. When I set the video player settings to 6 channels, only the front left and right speakers work. Tell me what needs to be done to get real 5.1 sound in movies and games.