I saw this last night and tried to figure it out, but I fell asleep before I got back to it. Sorry. :P
Anyway, I'm not sure exactly what you're trying to do here. Changing the level isn't all that hard - MeGUI can do it, tsMuxer can do it, whatever program the guide's telling you can obviously do it.
But what are you trying to do with this? Stream it using TVersity? If so, I believe you won't be able to, because TVersity can't stream .mkv files.
I remember seeing another streaming program (Playstation Media Server or something) that could stream .mkv, but I don't remember where the thread is.
...I dunno, does that help at all?
Additionally, if you're streaming and nothing shows up, it could be because you're doing so over a wireless connection. And if it's not that, then it might be that the video simply wasn't encoded with the PS3 in mind. In that case, you'll have to re-encode the video (which'll take a long time).