Calc Add-in Java extension: assign function to a new category

Hi all,

I develop a Calc Add-In with huge set of sheet functions. I would like
to put them into a new category.

In LibO Calc Java extension, in XAddIn interface there're 2 functions:
getProgrammaticCategoryName() and getDisplayCategoryName(). From
Javadoc I see that getProgrammaticCategoryName must return one of
existing categories, while I would like to have a new one.

It is not clear if getDisplayCategoryName can return a new category.
But it is not called anyway, as I can see from logs.

Is it possible to create a new category?

I posted this question at stackoverflow too:
http://stackoverflow.com/q/31777014/1028256

TIA,
Mike