Cakewalk FA-66: No Sound From Headphones

Greetings:
I have a Macbook Pro attached to a Thunderbolt Display docking station, and I've spent the evening setting up the new FA-66 audio interface I ordered last week. I have OS X 10.8.3 Mountain Lion. I previously been using a Tascam FireOne audio interface, which is another Firewire device.

Seems like the FA-66 was plug-and-play in that I was able to get my monitors to output sound (they are using Outputs 1 & 2 attached on the rear of the unit). However, the main issue I'm running into is that I'm unable to get any sound to output from the headphone jack. The direct monitor knob only has its "mix" through the speaker, but then goes quiet on the other end with no headphone output.

I know that my headphone works, because I pulled the unit and plugged my Tascam interface in, and sound came through the headphones just fine.

The settings in Sound in System Preference were correct, and I've even gone so far as switching from bus power to using the power adapter, but still no go.

Any assistance to help rectify the issue would be appreciated; thanks a lot.

Best,
Velanche