How can I place a circular (curved/round) stair in Hexagon Smart 3D using a custom command in C#?

I can create a straight stair in Hexagon Smart 3D using:

Stair stair = new Stair(system, part, top, bottom, reference);

and set standard properties such as width and angle.

Is there a way to create a circular/curved/spiral stair through the Smart 3D API or a custom command? Are there any stair properties or APIs that support curved stairs, or would this require creating a custom stair symbol/SmartPart?

I'm using the Smart 3D .NET API (C#).