Problem with swiss-german on testing / unstable

[Uwe Dippel <udippel@uniten.edu.my>]

I need some help on keyboard layout; can anyone point me to a good
description ?
This is the trouble: I'm using Swiss-German as keyboard layout. Using
dpkg-reconfigure I could set the non-X behaviour to be okay (qwertz, Alt
Gr 2 = <at>.
When I start X, however, it won't. With "us" in XF86Config-4 I get a
'good' qwerty, us.
With "sg" as "XkbLayout", I get the correct qwertz, Umlaute äöü, but
all Alt Gr is dead. Since backslash and <at> are Alt Gr 2 resp. Alt Gr <,
this is really troublesome !
What I'm getting instead, are 
(arg: 2) for Alt Gr 2 and a former user input for Alt Gr <.

"Works for me" won't help, since I have another machine on Unstable, for
which it actually does work without problem. And i have no clue, why it
wouldn't here. There is not much of a difference, both are USB-keyboards.
And I even upgraded the current machine from Testing to Unstable; but
without any change on this.

Thanks in Advance !