V_Maiko, water pandora is great idea. You are trying to force game to generate new subtype boxes, right? But you can place normal box on the water surface and then replace its .def, don't you? Or that is principal?

About the sound - with and without mod i have the same sound via interacting the box. This Mystery.wav file is missing in my game or something i cannot understand about your words. Should i upload some video?