From AVSforum as per KenH:
For those who are getting the 5.1 lamp lit, and only getting main L/R audio, try setting your DTV receiver to output PCM audio (if it can), then you can use Pro Logic processing. The last resort is to use analog L/R audio, which can also be processed with Pro Logic.
There is NO audio coming from the network for the center channel, LFE, or surround channels. Your local station should not have their Dolby encoder in the 5.1 channel mode. ABC sent us a notification yesterday that this game would be in STEREO not 5.1. The notification said nothing about Circle Surround. The second game is supposed to be in 5.1 per ABC.