Sitl, smart rtl

Hi, I am using SITL and tried to change mode to SmartRTL, but there is an error MODE: Unknown mode: SMART_RTL. I also tried with: SmartRTL, SRTL, SMARTRTL. I change mode by mavros/set_mode service, and it works with GUIDED, AUTO and RTL. I run SITL with command: …/Tools/autotest/ -L Simple -v ArduCopter --console --map. First I fly in AUTO mode defining waypoints to mission, and at the end I want to SmartRTL.
How can I change mode to SmartRTL?