I've develop a chat server using Twisted framework in Python.  It works fine with a Telnet client.  But when I use my flash client problem appear...  
(the flash client work find with my old php chat server, I rewrote the server in python to gain performance) 
The connexion is establish between the flash client and the twisted server: XMLSocket .onConnect return TRUE. So it's not a problem of permission with the policy file.  
I'm not able to send any message from Flash clien with XMLSOCket function send(), nothing is receive on th server side.  I tried to end those message with '\n' or '\n\0' or '\0' without succes.
You have any clue?
I find out that the default delimiter for line, use by Twisted is '\r\n'.  It can be overwrite in a your children class with:
LineOnlyReceiver.delimiter = '\n'
Chat server with Twisted framework in python can't receive data from flash client