This is an item where the workflow (philosophy) is different from a polygon modeler.
In a polygon world you typically make an outline, then lathe it or extrude it, then use some plugin to carve a bevel along an edge.
In spline modeling, you typically include the bevel shape in your outline, Then do the lathe or extrude. It's possible to stitch in a bevel after the fact but easier to put it in the outline before hand.