keyboard layout problems

[gettingout]

Good afternoon.

I have a problem with keyboard layout using xfce4. I've searched inside 
the settings manager without results. I've used google to search inside 
the ML archive and on the web but with no results.

I can't type any character that is combining with the ALT-GR key (like 
@#). I can do it in console tty1,2,.. and inside xterm but I can't do it 
inside thunderbird, mozilla, gvim, xfce-notes (for example). In all 
graphic programs (except xterm) I can't use the alt-gr key.

Before doing some operations I canned not (is it right english?) use it 
nor in tty1 nor in xterm. To use in tty1 it was ok only using the 
dpkg-reconfigure console-data and selecting the 
pc/querty/italian/standard/strandard keyboard.

To make it work under xterm I had to make the file /etc/X11/Xmodmap with 
inside a line like this
	keycode 113 = ISO_Level3_Shift
and now it work in xterm too.
Unfortunly it's not running in others graphic application.

I'm using debian sarge, with kernel 2.6.3, xfree 4.3, xfce4.0.6 all, 
gdm, all debian packaged. Here are some other information

Section "InputDevice"
         Identifier      "Generic Keyboard"
         Driver          "keyboard"
         Option          "CoreKeyboard"
         Option          "XkbRules"      "xfree86"
         Option          "XkbModel"      "pc105"
         Option          "XkbLayout"     "it"
EndSection

thanks a lot
Bye
Davide