If anybody that is really big on keyboard issues and is a pratictioner of this kinds of Dark Magic, please give us some help, we didn't have to sort these issues on RH 8.
I thought this sort of thing was normally done with X's "multi key".
I have a script that just runs one command:
#! /bin/sh xmodmap -e "keysym Menu = Multi_key"
It's just in a script to avoid quoting issue's with Gnome's session manager... So the session manager calls this script every time I log in, and the Menu key on my keyboard becomes a compose key. Hence, I can compose characters like so:
Menu ' c: Ä Menu , c: Ã
Is that what you're looking for?