To begin with I would strongly recommend you get autorun disabled as it is one of the primary infection methods for a LOT of malware.
There is a sourceforge project that replaces the U3 launchpad that looks good -
http://sourceforge.net/projects/u3-autorun/
As mentioned, you should track down an infected host and submit the executales to Symantec for analysis.
I also submit them to VirusTotal so I can have a clear picture of which vendors are detecting it.
You can then follow the different vendors writeups for technical details. Quite often someone will have a much better writeup than everyone else.
You can also grab the lates rapid release definitions and see if that detects the threat:
http://definitions.symantec.com/defs/rapidrelease/
Then you know that when the defs are released tomorrow all of your clients will be protected.
Still submit the file though, as Symantec will reply and let you know if it is a new threat, or one that will be detected by a certain definition sequence.
Good luck with it.