Hi Anand,
it works also for solids constructed from primitives. But you have to use it before adding it to the CSGeometry, see attached file.
To handle meshes without geometry I really would recommend xfem.
It is somehow possible to use your own integration rule, where you specify the according integration points, but the first option is easier, more robust and more flexible.
What error occurs when you try to get ngsxfem running?
Best,
Michael