[Paraview] HOWto create / extend sources?

[B.W.H. van Beest]

Hello,

I just can;'t figure out how how to do the following in Paraview
(programmatically, that is. I'm writing a new C++plugin). I found
description/examples of how to create youre own reader, writer, filter.
But what about a new Source?  In particular:
a) How to create a new source ("MyNewSource")
b) How can I extend an existing source (box, sphere, etc.) with new
properties and methods ("MyBox, "MySphere").

Any help or suggestions are greatly appreciated.

Kind Regards,
Bertwim