How do I trust a file, or have NAV ignore it when scanning?

I have a compressed .MSI file on my system in c:\windows\installer\ that I trust, but that NAV 2009 keeps telling me is a "Low" risk due to heuristics detection.  There are a total of 10 files detected in the Norton user base.

 

I've gone into Norton File Insight and set it to "User Trusted", but I keep getting the "Action Required" pop-up, with no option but to delete the file.  I've run Live Update and rebooted the system repeatedly, but I keep getting the pop-up.

 

How can I tell NAV 2009 to stop bugging me about this file?  If I can't stop this, I will be forced to uninstall Norton until y'all can figure a way to allow users to actually manage the files on their systems.