Firewire Solo Encoded output problem

I cannot set Firewire Solo (encoded output) as primary sound output in system preferences / sound / output section, because it does not appear in that list... I remember that there was this option in the past... but it disappeared since last two updates (I don't remember exactly as I needed this output right now)

I have to select Spdif output from system preferences... that's all I need...

By the way... I'm not talking about "show device pairs as outputs" option in hardware section of M-audio's control panel... this only opens up stereo solutions... I need encoded one in order to use it passthrough...

I'm using macos 10.5.6 with 1.8.4-3 driver... I tried to find a solution for this problem everywhere... (literally !!!) HELP...!!!

I also tried to reinstall macosx... and I only have installed the driver right now... so.. no apps nor any drivers installed on my mac except from m-audio firewire driver...

PLEASE HELP..

 

Any one??? comments??? Are you able to select it??? Or I hallucinated about that output???