Hi everyone,
I apologize but I was away from internet those last days so I could not answer...
KSV you are bringing wonderful news. Thanks for spending time on this problem. Of course, I am still happy to share the joining method. As i told you, it is not "my" method and it is coming from the package pluzzdl, developed by chaoswizard and you can download it here:
http://code.google.com/p/tvdownloader/downloads/list
there is a discussion page on French ubuntu forums (i can give you the link if you can read French; and you will see that i brought my modest contribution

).
Shortly, you have to retrieve part of the FLV header from the manifest file. There are in general, 3 different video qualities and for each you have (part of) the FLV header encrypted (one can use the base64 python package to decode it).
Then you have to strip the first bytes of the fragments before concatenating them (see the Pluzzdl.py in the package I pointed for more details). Let me know if you don't find the code snippet... I reassure you I don't want to broadcast it on my webpage. Besides, i don't have time to have a webpage
About TVO and Captvty, those are windows software and I have been unable to make them work on linux. And I don't think I am the only one.
Wishing you a nice end of week.