Another way for the future might be to use RTMFP (a udp-based protocol) and send data as though the sandboxed flash and the bridge were on separate computers. It assumes, however, that there's an enabling server for getting the two connections hooked up with each other; right now the only server that's available is adobe's stratus beta, but apparently the plan is to let people run their own servers.
http://codereview.appspot.com/116048
