How to use brep.addsurface?

Hi everyone,

I'm trying this:

Dim brep_object As Brep
For p = 0 To surface_list.Count - 1
   brep_object.AddSurface(surface_list(p))
Next

to add a lot of surfaces that I created with the NurbsSurface.CreateFromCorners function to a brep object. But it doesn't work.

Then I would like to create a solid out of each brep object, I found this thread that explains to input a brep list:

http://www.grasshopper3d.com/forum/topics/running-a-macro-that-bakes-a

Thanks for any help,
Fernando