All newsgroups are the same. People upload what they have either by request or just randomely.
Just make a request post for it. If someone reads it, and has it, they may post it.
Depending on your isp's server retention, files can drop off within 24 hours, so its a "download while you can" setup. Its not like a webserver for a site where someone might stick an mpeg, zip, etc on their site for eternity. Usenet(the newsgroups) is a temporary function, more similar to what napster, and now Kazaa are, than site uploads.
Usenet is great, i collected all the West Wing Episodes from it. The Disney one i posted and you're going into has had a recent flood of Dutch posters, hence how many files have jumbled lettering. Usenet, like the web, is mostly english-based, but open to anyone with access around the world. There's a regular bunch of posters that seem to have a ton of great attraction vids, disney albums, you name it.