pdf-writer and new page sizes

Hi all,

We are creating pdf documents using pdf-writer, and are pretty happy with
the results. The only sticking point is we need to create pages of
different sizes. Does anyone have any idea of whether this can be done
using pdf-writer? And if not, does anyone have a suggestion of the best
way to do it? I tried using prawn, and couldn't get images to behave

Cheers Simon