Cisco: you have to watch your bandwidth much more when viewing from Ch9 than if you just download TV using BitTorrent or rapidshare. Why? They average 800Mb from Ch9 an episode vs. 350Mb via BT. There's no good reason for the size - the picture quality is apparently pretty bad (compared to standard 720p), it's just that their player/plugin just uses a crappy codec and there's extra downloading for DRM and ads.
The reason Underbelly won't play anymore for you is that the DRM built in has decided that you've had your chance and you're time is up.
So in summary: you have to use more than twice the bandwidth to get a lower quality picture, with ads that you can't skip, and the file self destructs after an unknown time. Not much of an incentive to do it their way, is it?

Having said that, aussie shows are harder to find than US/UK.. it often helps to get them right after they air. After a quick search I did find the whole 13 ep first season of Canal Road available as a single 4.2Gb download (same as 5 eps via Ch9).