Because I couldn't find the wiki page posted, here the short description I was missing out on in the beginning. I'm using Kamikaze 7.09 and to make it work there you need to install the "hotplug2" package first. With my system some hotplug scripts already came (the ones required for booting) without the hotplug2 engine itself. That confused me a bit.
I put this script in /etc/hotplug.d/button/30-button-trigger:
if [ "${ACTION}" == "released" ]
then
/usr/sbin/wlan-button
fi
Whenever any button is "released", the /usr/sbin/wlan-button script is started. It looks like this:
#!/bin/sh
if [ `wlc radio` == "1" ]
then
wlc radio 0
else
wlc radio 1
fi
I leave it as an exercise to the implementor to make it work only with the "ses" button.