An idea: you could open a socket connection (because of corporate proxies best would be the port 80) and try to read an integer:
private function handleTcpData(event:Event):void { while(_socket.bytesAvailable) { try{ var i:int = _socket.readInt(); fetchHttpData(i); }catch(e:Error){ // incomplete integer, will be read by another handleTcpData call return; } } } and whenever an integer arrives from your backend, your client could read the whole data over HTTP. Regards Alex