The pinout from the diagram is standard OTG. Pin 4 (sense) and 5 (ground) are tied together on both ends, this gives the OTG configuration regardless of which end is plugged into the phone.. Other than that It really looks like a standard USB OTG cable from their diagram. I begin to think the magic is in the circuit in the HA-2.
The only reason that I can think that the TTVJ cable would be "directional" is if only one end has pin 4 and 5 tied together. Maybe the Glacier DAC/AMP doesn't like these pins being tied together. This still gives the "sense" line to the phone so it will see that it has an OTG connection. (or so I believe)
Anyway, I ordered one. I will give it a try and let people here know what I find.