Setting chapter numbers, ...

Hi list,

I'm new to DocBook XML/XSL and I have a few simple questions for which I
didn't find an answer yet. Primarily I want to generate PDF's.

1) Is there an alternative mechanism to rootid for selecting arbitrary
chapters (so that the chapter numbers are preserved).

2) Or is it possible to set the chapter numbers manually.

3) Is it possible to switch for some pages from two column layout to
"normal" layout. How is it with switching from A4 paper (portrait) to A3
paper (landscape) - also only for some pages.

4) Is there a way to define tables and figures spanning over two columns.

Best regards,
Bjoern