Thanks for your reply.
So I understand that Pro/E doesn't permit to lay (as a sheet) a solid geometry.
Regarding the suggestion to use Sheetmetal, I think it is not possible converting the original geometry because it hasn't a constant thisknes. See the image below:
The only feature I considered to use is Flatten Quilt / Flatten Quilt Deformation, but I think I cannot warp the geometry on a spherical surface (only cilindrical..)