Games : How do I get the xbox live patch? For more maps and hero assault?

I have been reading in various places that the Hero Assault mode in Battlefront 2 (available by default only on the Mos Eisley map) is available on more maps with an xbox live patch.

I've been trying to figure out how on earth to get this patch, and I can't figure it out. I'm playing on a 360, and I'm a little worried it just doesn't really apply.

I want to play Hero Assault on more maps!