Support for the Xbox 360 has landed in master. You need:
- gupnp
master0.13.3 - gunp-av
master0.5.5 - gupnp-vala
master0.6.5 - rygel master
For the transcoding to work properly make sure you have gst-lame and gst-ffmpeg installed.
On a side note: Rygel master has now gained the ability to serve subtitles to Samsung DLNA enabled TVs