[Libreoffice] [MHST][Easy Hack] Get current page number for printing

Hi,

We are trying to hack into this easy hack
https://bugs.freedesktop.org/show_bug.cgi?id=38830
We're still studying source code. We have 2 questions:

    1. How to get current page number for printing?
        We've found a variable mnCurPage from printdlg.cxx but it seems 
not to be the right one. I think it is current page number for preview 
in print dialog.

    2. How to add another RadioButton in to print dialog?
        We can enable and disable existing RadioButton like All, Pages, 
or Selection but it's still mystery for adding new RadioButton. We want 
to add a Current Page radio button just below Pages radio button.

Anyone please help us :)

Thanks and Best Regards,
TaTung