After all, the "ß" is just a ligature of "ss" (or, to be precise: a ligature of "sz", originating from old German fonts - see hyperlink below), so I suggest the rendered outcome of the capital "ß" to be just the same: A ligature of two capital "S".
Here's a hyperlink to an old German font (notice the lower case "s" and "z"): http://www.myfont.de/fonts/infos/5602-Koch-Fette-Deutsche-Schrift.html