I honestly don´t think those three networks are available here, at least I cannot watch them with Cablevision one of the major cable companies. Some other cable companies are listed on http://www.indextar.com/ba/buenos-aires-recreation-and-leisure-television-c316
You can check out their sites and see if you find those networks... although others such as CNN, ESPN, The Entertainment network and the BBC are widely available.
As the previous poster has mentioned, CNN and BBC are available. So also are Deutsche Welle (German channel, but with English coverage) and Tvsmonde (French), as well as at least one channel from Spain.
I find the European channels somewhat more balanced and less biased, less hysterical, but I suppose it's a matter of opinion and taste.
If you have a high-speed internet connection you can download TVU player which has these networks and many more. If you go to the full-screen mode though it diminishes the quality and connection. If you keep it on the 5x7 inch screen most of the time it keeps a decent connection. Except during big games when there are a lot of people logging on. Then the stream is more spotty. Do a google search on TVU player to get the download.