Nobody from Syabas responded but a mod did - check out
From my reading of this it seems that the Sigma designs SDK does not support this audio format. So Syabas can't do anything (even if they wanted to) to decode this audio until the SDK is updated. The only other solution is for Syabas to take the Monogram DS filter code that Sub is using in gbpvr and write the code themselves into the firmware. With only two countries (I think) using this audio format on DVB-T broadcasts (why on earth did Kordia decide on this strange codec) I think the number of users who would benefit isn't exactly high.
So we are still screwed unless when TV1 and TV2 go proper HD they choose to also broadcast AC-3 audio as TV3 does. Then we don't care I guess.