Why PCM 44.1 KHz?Below you can see my personal settings for Asus Xonar Center.
Try to set your default playback device to "Asux Xonar Speakers" this is the right setting for HDMI Bitstreaming!
The Digital S/Pdif Xonar Device is only for DTS and Dolby Passthrough and NOT for bitstreaming HD Codecs ... as stated in the Xonar FAQ...
It's like using TMT3 for HDMI passthrough...
After that your Dolby True HD Light on your receiver will light up ... at least it did for me...
And don't forget to register the arcsoft decoder!