Where is the Lost Helicopter Alarm?

Just received my new Pixhawk and am preparing its settings. I usually reserve Ch 7 for RTL and had previously no function for Ch 8. While browsing thru Channel 7 & 8 options (http://copter.ardupilot.com/wiki/channel-7-and-8-options/#check_ch7_ch8_pwm_values_reach_1800) I noticed a useful function: Lost Helicopter Alarm. That seemed to me a good function as I once almost lost a quad in the maize.

However, I can’t find it in the options of Mission Planner for Ch 7 & 8. On the other hand: I found a lot of options which weren’t documented anywhere (what to think of EPM, EKF, Relay, etc?). So is there still a Lost Helicopter Alarm, has it been renamed (another page mentions Buzzer but that exists neither) or should I do some trickery to get it working?

Thanks in advance!