Hi @Michele100100
Section is presented symmetrically for both sides of neutral axis.
You can define sloped member neutral axis or you can define offset for one member end (use Geometry >Additional attributes >Offsets). In my opinion it is not necessary.
I think that results for beam defined by default (as on your screenshot without sloped axis or offset) will be good enough for static analysis. Keep in mind that while calculation, geometry - defined by neutral axis) and stiffness - defined by section properties (numbers) is used for analysis. Section shape is only graphical presentation and it is not considered while analysis. It is important for workshop drawings but not for calculations.

Krzysztof Wasik