Cannot create a Cross Section with Steel material in SOFiSTiK (Rhino Interface)

Hello everyone,

I’m working with SOFiSTiK through the Rhino Interface to model a membrane with masts and cables.
My masts are defined as Truss Elements in Rhino.

Problem: when I try to create a Circular Cross Section for these masts in SOFiSTiK SSD, my Steel material does not appear in the Material dropdown list inside the Cross Section dialog.

What I’ve tried so far:
• Created a new Steel EN 1993 material (S355) in Materials with E = 210000 MPa, ν = 0.3, ρ = 78.5 kN/m³, fy = 355 MPa
• Created a circular section in Cross Sections and tried to assign this material
• Checked that the material has a valid number and is set to type Steel

But the Material list in the Cross Section dialog still only shows default timber/concrete materials — no steel option.

How can configure SOFiSTiK (SSD/Rhino Interface) so that my Steel material appears when creating a circular cross section that can be assigned to my Truss elements?

Thanks in advance for your help!