I just got a Hitachi LED tv and a Samsung HW-E450. The tv has a HDMI Arc port.
When I connected the HDMI cord from the HDMI arc on the tv to the HDMI out on soundbar, it produced no sound. The CEC control was on , as well as the Anynet+. Additionally, I could control the soundbar through the tv, I could "raise" and "lower" the volume, turn the soundbar on and off, however, it would not produce any sound.
I had a ps3 and cable box hooked up to the additional hdmi ports. The soundbar works, as it worked through the bluetooth setting. For some reason though, it will recognize the TV ARC, but it will not produce any sound.