Carbon port: M-§ not recognized (Italian ke yboards)

[David Reitter]

It seems like M-§ isn't recognized as such on Italian keyboards in  
the Mac (Carbon) port.
define-key for this sequence doesn't show an effect, and the error  
message is
        
        M-¤ is undefined

suggesting that something goes wrong with back-translating the  
keycode in macterm.c.
Does anyone have a good suggestion about the underlying cause of this?

Note that this is with (setq mac-option-modifier 'meta).

Option-§ is - by default - bound to @ under OS X, so getting that key  
to work properly would bear some significance, because people might  
want to manually bind this key to something like (insert "@").]

(Apart from that, "\M-(" gives me a nice "\250", while "\M-§" gives  
me just "§". I assume this has traditional reasons.)