Import files into a media library using REST

longin-natgas

I'm currently having trouble importing a file into a existing Media library via REST service. Basic functionality is working, I can query the media libaries content via Fiddler and a c# code snippet.

First thing: Which URL do I have to address for an insert - I used

http://localhost:6666/rest/media.library/3/children/media.file

to get the content of the appropriate media library, but what is the address if I want to insert something ?
Second thing: If I did understand the documentation correctly I have to encapsulate the metadata in a "data" tag and put it into the header of the post request.
Which fields of the "Media_File" XML structure are mandatory, and how to put that into the header. Hints for doing it with fiddler would be nice, but I wouldn't mind some c# code either

thanks