Really annoying - the temperature variable is CurrentTemperature, not CurrentLevel for temperature sensors. It’s here:
http://wiki.micasaverde.com/index.php/Luup_Devices#Variables_8
Spent a few minutes wondering what was wrong with my API call to the controller querying temperatures; didn’t realize the wrong variable name until I queried the user_data XML and parsed the page. CurrentLevel is valid for light and humidity sensors, but not temp sensors.