You need a registry editor.

Go to HKCU\ControlPanel\Notifications\Default

Under Wave, change the value to whatever file name that you want.

NOTE: The value name must be stored in your Windows\ in order to work.

Enjoy

How about changing the path to Storage Card? How do we change this?

Thanks

So far for that notification, can only assign to windows directory.

as for other ring tone directory you can assign to your storage card.