A quick update, I was able to get my ODAC detected under the Audio output and set it as default. This feature was enabled after I went into the Raspbmc (running the latest Gotham 13.1 I think version) settings and enabled the external sound card feature. But initially it was not detected and then I realized that I had connected the ODAC directly to the PI, so now connected it using a powered Belkin USB hub and it works now without any issues. The quality of WAV/FLAC music is very good but unfortunately unable to get the sound over DAC for video playback. It seems thats how its going to work for videos with external sound card as the video gets played over HDMI by default for both video/audio.