Assuming your TV is only ARC and not eARC then with either connection method you would need to have your setting showing expert so you can see all the options and then turn on in the audio settings 2 channel, passthrough on, and enable passthough for AC3 and DTS.
I did try the above. Now getting DD 5.1 (640 Kbps) but no DTS. I did enable all passthrough and even rebooted the unit. Looks like I need to invest in HDFury.
Since your now connected via HDMI directly to the soundbar the optimal settings would probably be to select 7.1 channels with the supported passthough formats enabled.