Fill a spline

[slester]

Hi,

I'm trying to fill a spline thanks to MeshHelper.CreateSplineMesh().
I explain the problem:
i create wall a runtime by clicking and adding control point in a spline + meshbuilder. if the first and the last control point are near enought, the spline shut itself and i want to add
a roof the the wall thanks to MeshHelper.CreateSplineMesh(). 
It kinda works sometime. i have some triangle wiwh are drawn. but not all the surface.
sometime the faces normal are switched with no reason.
and finally i don't understand how the curvation angle works in the function.

here a picture to have a better idea: http://hpics.li/25264cb
Could you please give some information about this function and tell me if what i wanna do is possible.

Thanks