If you create now the vault using Rhino surfaces and you offset those surfaces to create different layers, all them will appear in VisualARQ section views.
In the 1.8 version you will be able to assign section attributes…"
Right now it is not possible to extend walls to meshes. I will add this request to the wishlist.
If you want to convert the mesh into a polysurface, it might take time depending on the mesh detail.
But also take into account…"