Norton Internet Security (NIS) removes ability to turn off Network Discovery/File Sharing

History:
1. When connecting to shared printer on XP machine (alex-pc-xp), on Vista, I
activated Control Panel?Network and Sharing Center "Network Discovery"=On
and "File Sharing"=On. I didn't need to, but I did anyway.
2. I'm no longer able to turn Off the above two settings.
3. If I turn Personal Firewall=On in Norton Internet Security (NIS), then I
am able to turn the two settings Off, however, as soon as I turn Personal
Firewall=Off and close the Norton GUI, the above settings are back On with
yellow text in Network and Sharing Center: "For sharing and discovery to
work properly, make sure the settings in your firewall program match the
following settings."
4. See
a.
http://forums.microsoft.com/TechNet/...6004&SiteID=17 -
" I suspect that Vista might have been preventing you from turning off
file-sharing, because the network (i.e., your XP machine) was already
included in Norton 360's Trusted list." and
b.
http://forums.microsoft.com/technet/...3125&siteid=17
"Once file sharing and network discovery are turned on and functional by
applying the above firewall settings, you won't be able to switch them off
using the corresponding option buttons in the Vista Network and Sharing
window. If you attempt this (by clicking the down-arrow button to the
right), you'll see a notification saying that the option is now controlled
by the firewall program. So you'll have to manually remove the trusts from
Norton 360 or Internet Security. "

The article above, although document, don't advise on how to re-enable my
ability to control Discovery/File Sharing.
Note: I checked Norton's Trust Control and I cannot see anything like
alex-pc-xp or its IP address.

Any advice please?