I had no trouble getting smartthings to add it, but I think I recall it adding as a regular dimmer (or maybe a multichannel device). After adding it, I logged into the IDE and changed the device type to use the custom handler from here: https://github.com/mlebaugh/smartthings/tree/master/devicetypes/mlebaugh
Recommend you check this thread: Jasco/GE Motion Dimmer Switch 26933