I'll also update the wiki to explain all the aux functions.
One thing to be aware of is that we have two "avoidance" features. We have "ADSB avoidance" (i.e. avoidance of manned aircraft using an ADSB sensor) and "object avoidance" (avoidance of near-by obstacles).
ADSB Avoidance: http://ardupilot.org/copter/docs/common-ads-b-receiver.html
Object Avoidance: http://ardupilot.org/copter/docs/common-lightware-sf40c-objectavoidance.html
The auxiliary switch options were not clearly labelled in AC3.4 and if you're using stable mission planner then it's using the older labels in which case you may just see "Avoidance" which mean "ADSB Avoidance". If you use beta MP or just wait until AC3.5 is released as the official version you'll then see two more clearly labelled options, "ADSB-Avoidance" (CH7_OPT=38) and "Object Avoidance" (CH7_OPT=40).
Sorry for the confusion.