Binding keys F13 to F17

[Til Schubbe]

Hello,

I use a Cherry G80-5000, which has 5 additional function-keys
(F13-F17) on the left side. The layout is like this:
xkeycaps -kbd CHERGODE

I like to bind a pipe/bar ("|") to F17.

By pressing F17 xev tells:
--->8---
KeyPress event, serial 33, synthetic NO, window 0x6600001,  
    root 0xea, subw 0x0, time 34016738, (-545,-52), root:(552,763),
    state 0x0, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyPress event, serial 33, synthetic NO, window 0x6600001,
    root 0xea, subw 0x0, time 34016744, (-545,-52), root:(552,763),
    state 0x1, keycode 73 (keysym 0xffc4, F7), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 33, synthetic NO, window 0x6600001,
    root 0xea, subw 0x0, time 34016753, (-545,-52), root:(552,763),
    state 0x1, keycode 73 (keysym 0xffc4, F7), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False   

KeyRelease event, serial 33, synthetic NO, window 0x6600001,
    root 0xea, subw 0x0, time 34016763, (-545,-52), root:(552,763),
    state 0x1, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False
--->8---

By releasing F17, no event is being generated.

As far as I can see, F17 (and F13-F16, too) has not been assigned
a seperate keycode. But pressing F17 simulates 2 KeyPress events of
other keys (Shift_L and F7). So, how can I assign a character to a
key without that key having an own keycode?

xmodmap -pke doesn't tell anything about F17.

Having read /usr/include/X11/keysymdef.h I tried
xmodmap -e "keycode 0xffce = bar"
but without any effect.

Might the keyboard-controller itself generate the 4 events cited
above? Does the kernel really get the info of F17 being pressed?

How can I assign a bar ("|") to F17?

I run
X.Org X Server 1.7.7
Release Date: 2010-05-04
X Protocol Version 11, Revision 0
with Debian Squeeze.

In xorg.conf I have:
        Driver      "keyboard"
        Option      "CoreKeyboard"
        Option "XkbRules" "xfree86"
        Option "XkbModel" "pc105"
        Option "XkbLayout" "de"
        Option "XkbVariant" "nodeadkeys"

TIA
Til