The LocalFileSettingsProvider does not provide a way to change the files in which settings are stored.
Note: The provider itself doesn't determine the config file locations in the first place - it is the configuration system.
If you need to store the settings in a different location for some reason, the recommended way is to write your own SettingsProvider. This is fairly simple to implement and you can find samples in the .NET 2.0 SDK that show how to do this. Keep in mind however that you may run into the same isolation issues mentioned above.