Checked with @samsungservice on Twitter
They gave the following response, which I think is what Mr. Shaun Warburton suggested above. I don't know why she says there is no way to adjust the audio on the sound bar using the TV remote, since that seems to work fine even with just an HDMI connection.
"To have the Soundbar turn on when
the TV is powered on you must disable Anynet on the SoundBar & use optical
cable connection. When TV is powered on,
the SoundBar will turn on. When TV is powered off, the sound bar will turn off
after 20 mins when it doesn't detect a signal. When using HDMI connection,
w/Anynet on, you can use SoundBar remote to control only TV Power/TV Info/TV Ch.
There is no way to adjust the audio on the SoundBar using the TV remote or vise