I've discovered a simpler way for exporting models if you're fine with resetting the file in the older version (I haven't tried importing the file with 2009 features this way yet). You should download the expansion where you get extra export features. Download this (might already be installed if you have maya 2008/09/10 unlimited, not sure about standard), and turn it on in the plug-in manager. You should be able to export whatever model(s) you're working on in any version into an older/newer version.
I hope this works out for anyone who's still asking the same question.