Google Analytics Plugin: Modify for Subdomains

I would like to make the Google Analytics plugin work across my entire MU/BuddyPress install (easy), the difficult part is implementing these instructions:

http://www.google.com/support/googleanalytics/bin/answer.py?hl=en&answer=55524

Since I only add the tracking code (Ex: UA-XXXXX-2) in the options page, then how do I add this line:

pageTracker._setDomainName(".example.com":wink:;

Thanks!