We've been putting together a kit at the hackerspace to support doing all of the Adafruit Raspberry Pi tutorials. While working through the tutorials I've gotten stuck on Tutorial 8. I switched to from Raspbian to Occidentalis 0.2 to get the PWM feature. However, the files that are supposed to reside in /sys/class/rpi-pwm/pwm0/ don't seem to exist (actually, the whole tree from rpi-pwm on down is missing). Is there a step that I'm missing that "activates" a module to create the necessary files, or some other secret sauce?