Simply supported beam with S8R elements in Calculix

Hello,

It's my first post here in this forum and I don't know if here's the right place for this question.

Does anyone know how to set the constraints to a composite beam made of shell elements in CalculiX?

In its manual there is a cantilever beam, which is fine. However when trying to apply simply supported conditions to the bottom of each end of the beam, the boundary conditions which were supposed to give a simply supported beam end up giving a hinged conditions to both ends of the beam.

Is there a way to move these conditions to the bottom of the beam (the lowest element nodes)?

Thanks for you time in advance.