Comment 53 for bug 313514

I made a quick fix for this problem. It's based on kbd's showkey that DOES show scancodes. It looks into configuration table and stuffs required keysyms into X via Xtst package. Ugly, buggy and setuid (to read console under X you have to be setuid), but it works (at least for me) and requires only installation of the deb package. Lucid package is here:

add-apt-repository ppa:rm-isaev/rawkeybind
apt-get update
apt-get install rawkeybind

Source code: http://www.isaev.ru/rawkeybind/

By default zoom up and down are bound to up arrow and down arrow but you can change it in /etc/rawkeybind.conf