Comment 5 for bug 694222

Turns out tpconfig requires raw access which is not provided by /dev/psaux. So doing it the right way produced:
#rmmod psmouse
#echo -n "serio_raw" >/sys/bus/serio/devices/serio1/drvctl
#tpconfig -d /dev/serio_raw0 -i

fatal:

No Synaptics or ALPS touchpad device found