Structural member on a 3D imported curve (Rhino3D file)

Hi all Solidworks community, hope you can help me.

Here's my deal:

I need to put structural member on a imported curve form a from 3D Rhino model file (it's a spline)

So I try to sketch arc over it but it didn't work well.

I need to put HSS 5.563 over it

Thank you 

SolidworksModeling And Assemblies