My Reply #6 above your post isn't related to the system restore issue/confusion, but directly about a test I did.
This test with a benign anti-virus test file, eicar.com, it should answer the question on how to add to exclusions, as Restoration would appear to do that. I suggest reading my previous post again.
Thank you for your clarification. It seems that Avast is adding an exception somewhere after a restore, which means you must be careful what you restore, especially since it may be difficult to find, since you don't know the path.
I just ran a test to see what Avast files change after a restoration, using a utility called InCtrl5, which records the state of all files when it's run & then again when it's run the 2nd time.
I recorded all files, & then restored a program from the virus chest which is not actually installed on my computer...PestPatrolV4.exe. Then I ran InCtrl5 again. As you noticed, Avast would no longer flag PestPatrolV4.exe as a virus. InCtrl5 found 2 Avast files that had been changed after the restoration.
1) c:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\lscache.dat
2) c:\Documents and Settings\All Users\Application Data\AVAST Software\Avast\chest\index.xml
So it appears that one of those files contains the "exception", but I'm unable to read either file.