windows key as super

[Giovanni Gigante <giov@cidoc.iuav.it>]

I am using emacs 22.2.1 on debian 5.0.3, through a VNC connection from a 
windows machine, and I am trying to configure the windows key for some 
emacs shortcut.
VNC is configured to "pass special keys directly to server".

Then I tried in emacs:
(global-set-key (kbd "s-s") 'save-buffer)

However, this does not seem to work. If I type "windows - s", all I get 
is an s.

According to xev, this is what happens when I tap the windows key in a 
terminal window:

KeyRelease event, serial 30, synthetic NO, window 0x2800001,
     root 0x2e, subw 0x0, time 118816809, (423,786), root:(448,849),
     state 0x0, keycode 255 (keysym 0xffeb, Super_L), same_screen YES,
     XLookupString gives 0 bytes:
     XFilterEvent returns: False

so it seems that the super key is being received after all, but emacs 
ignores it.

BTW, running emacs on the console (locally, sans VNC) gives the same result.
What am I doing wrong?

Thanks
Giovanni