For a keyboard-based switcher, you can try KeyHelper, a keyboard remapping program that just happens to also have a built in taskselector. There is a link to it and some information on setting it up available at: http://viz.aset.psu.edu/ga5in/SharpZaurus.html
I use it on my C760. I'm not sure if it will work on the 5600 or not, but it's worth a shot. The keycodes for the 5600 are probably different, so you'll have to find a list of them, or you can try the KeyHelperConf app, which is available at: http://yakty.s31.xrea.com/linuzau/keyhelperconf/
(warning: Japanese page).
anpachi, gifu, japan