xkeycaps, f30 keys

[Uwe Brauer]

Hello

I just changed a thinkpad laptop and noticed that me
keybinding does not work as in earlier models.
All Thinkpads I know have besides the left,up,down,right key
two other keys at the side of the up key
which in my .Xdefaults file are bound 
like this
keycode 234 = F30
keycode 233 = F31

Now in the new model, with the new Kubuntu (9.04) and  the
new X11 server this syntax has no effect. The 

expected since 
f30 is now renamed to XF86Forward 
f31 to XF86Back

I don't feel like changing my xemacs keybindings but would
like to redefine these two keys.

Problem old xkeycaps has no keyboard model with these
keys. How can I figure out which keycode corresponds to
these two keys?

Thanks 

Uwe Brauer