NSDialog Modify Progress Bar

I'm creating a custom dialog using NSDialog. I've integrated a progress bar in mypage and I would like to use it respectively show a progress.
I've skimmed http://nsis.sourceforge.net/Docs/nsDialogs/Readme.html , but found nothing helpfull.

Does someone now how to modify the progress bar?

Thanks
CJ

;$0 - from 0 to 100
SendMessage $ProgressBar_hwnd ${PBM_SETPOS} $0 ""

Thank you 🙂
I can just use numbers from 1 to 10, but it's better than nothing. 🙂 [Addition: I'm additionaly using MUI2 now and the range changed to 1 to 100.]

Where can I found information to this function and other ones?

Google is probably the easiest way, but all the information you'll need can be found in http://msdn.microsoft.com/

Thank you!! 🙂