Excluding a mapped network drive

I am running NIE 2010 on a desktop running Vista. I have a network drive mapped to my computer that is being included in the full system scans that I would like to exclude.  However, when I go into settings to select folders to exclude, the mapped drive is not listed.  Yet when I go and run another full scan it gets included once again.  I have tried logging off the drive, rebooting and remapping it, but the same thing happens.