It is currently impossible to creating "Composite Curves" and "Datum Curve from Points" through Datum Curve element tree. Please add these to Toolkit functionality.
From Creo 2 Toolkit documentation (M100): "Some other curve types, including Thru Points, From File, and Use Xsec do not currently use element trees in Creo Parametric, and are therefore not accessible via Creo Parametric TOOLKIT."
