Grasshopper - Archicad Live Connection - Driveway Creation

Wondering if someone could give me some guidance on how I can finish this off.
Have a mesh drawn in Archicad. Have also drawn a fill that represents the shape of the driveway I want.
In Grasshopper I can get as far as creating two open morphs which resemble the basic shape I want.
I can’t however thou figure out how to turn this result into something solid in Archicad, whether this be a morph, shell, mesh.

I should add that I’m only getting started with Rhino and GH.
With the above I have tried “Morph Solid” but that requires a Mesh as the input.
I’m not sure how I would convert the two curves into BREP if that’s a possible solution.

I’m sure there are 20 different ways to achieve the end result I’m after, so open to suggestions.