Restoring Files back to original state during uninstallation

[sjaug20]

Hi:
I have a very simple Install shield InstallScipt MSI installshield operation where I do the following on a folder that is already existent on the system
1. Add new files
2. Append some data to already existing files
3. Overwrite some existing files with newly modified versions of that file

However, when do an uninstall, it deletes the new files (ok, correct operation), it also deletes the files that were overwritten (bad, not what I want) and it leaves the appended file with the appended data.

Here's what I want to do during uninstall. I want to restore the overwritten and appended files back to the original file that existed prior to installation.

How can I achieve that? Is there a property setting that I can do?

[KathyMorey]

It sounds like the way to go is to write an InstallScript function to save the files during install and another to restore them during uninstall.