Is SpeedTree grass integrated with the Terrain system?

I can't seem to get SpeedTree grass to work with Unity Terrain system. I added it as a Detail Mesh etc like usual but it won't paint any of the speedtree grass.

I've also zoomed in very close and tested it in play mode to make sure I wasn't outside of the "grass drawing distance" or whatever. So I don't think that's my issue.

How is SpeedTree grass intended to be used in Unity?

thx for the help