Custom shapes Geometry data doesn't show in Heads up Display / Poly count

When creating custom shape using MPxSurfaceShape API, Maya heads up → polycount doesn’t show the geometry information.

For example, I create a custom cube but poly count heads up display doesn’t show anything

My original understanding was that once the custom shape is registered ( MFnPlugin::registerShape ) then Maya should recognized this information.

I also look at apiMeshShape example that ships with devkit and even that example have the same issue.

What should I provide through the API ( C++ ) so Maya show this information?

I am reading the doc but haven’t find what I am looking for.

Any help is appreciated.