Streaming multiple .flv files

I wasn't able to find any useful resources on the net for this particular setup, so it seems to be a pretty unexplored area or I'm just unable to use search engines, so here we go:
I've got multiple .flv files which need to be streamed in sequence, without noticeable gaps between them; the .flv files are going to be created dynamically, so there is no way to join them before the actual streaming takes place.

Now it should be possible to modify an existing flash video player in order to automatically get the next file while the current one is being played, but I'm wondering whether there's a way to having a single big .flv file and just appending additional files after they have been created.

Is it possible to make a streaming server "aware" of the changed file size? Or is HTTP streaming more appropriate in this case?

Any information or advice on the subject would be much appreciated!