xfce keyboard problem

[Joep L. Blom]

I have a small problem with my keyboard.
I'm using xfce on Ubuntu 10.04 (yes, I will upgrade shortly) but 
actually since I'm using xfce my right alt-switch, assigned to use third 
level keys won't work. However, when I look at /var/log/Xorg.0.log I see:
.......
(II) XINPUT: Adding extended input device "Microsoft Microsoft® 2.4GHz
Transceiver v8.0" (type: KEYBOARD)
(**) Option "xkb_rules" "evdev"
(**) Option "xkb_model" "pc105"
(**) Option "xkb_layout" "us"
(**) Option "xkb_options" "lv3:ralt_switch"
......
When I use "right-alt_switch+5" I expect to see € but it gives: (arg: 5).
So the X-driver recognizes it. Has anybody a clue why it doesn't work?
Thanks
Joep