File output from a RTP-stream

[Arateris]

Hy evryone.

For debug and test purposes, I need to save into file what VLC plays (at least what VLC decodes).
I tried using the Stream/save command in the Opening menu, I choose a file to write in, but when I stream the RTP from my server (Darwin), VLC debug message get full of errors, indicating that non-dated packets are trying to come...
With the same video ( h264 encoded), server configuration and VLC, in a normal output mode, it works well. So is there any problem in recording RTP streaming or how could I do??

I also tried to tick the box near the file browsing line ( I don't know it's name in English) but with this, VLC doesn't even manage to connect itself to the stream...

thx for helping.