In regard to configuration, if you look into the standard reports for Google Analytics, because you're only using one domain and not hosting a microsite that would require separate analytics, it's best to keep the same tracking code for the site. That way on the whole you can compare how much of your time spent on the mobile site is worth it or another way of looking at it is to see whether or not your mobile site is effective from a traffic standpoint.
To find out more about your mobile visitors, you can visit the Mobile Overview Report in Google Analytics (under standard reports on the Left).
Sorry bit of a disconnect. It's all related, but if you check out page 24 Search Engine Optimization Starter Guide PDF from Google, they tell you to create a Mobile Sitemap and submit it to Google so they know that the mobile section of the site exists. (Then you can use the Webmasters tools to see if the site is working for their mobile browsers, since this traffic is not tracked by GA.)
Additionally they tell you to check and see if the site is even showing up in a google search for the mobile content by visiting
site:example.com something on the mobile site. (For troubleshooting analytics not working on the mobile section of the site.)