System: HP9000 C110 Workstation with a PA-RISC 7200 chip
Key Board: 102 Key, PS/2, with British layout (IBM166 Layout)
Debian Linux 3.0r1 for PA-RISC

Background: All keys work correctly using the base system

Problem: In XFree86 the "| \" key is dead.

This key is on the second row from the bottom and the second key in from the left. i.e. Between left shift and Z.

showkey returns 86 for this key and this is reflected tin the file keycodes.
In XFree86 files in /etc/X11/xkb/* this key is referred to as 94 i.e. keycode+8 which appears to be the case for all keys. And it is also referred to as "LSGT"

Configuration: I used dpkg-reconfigure xserver-xfree86
Number of keys 102
Keyboard: us
Modifier: gb

This correctly modifies the ¬ `, ", £, @, and the ~# keys to reflect British usage.

Inspecting the gb file, key 86/94 seems correctly mapped but remains dead.