Render detail 2 at the bottom of the page before detail 1

[ogc002]

Hello everyone
How could I make my report paint first a detail band that is in the lower part and then the other that is in the upper part. I mean, I have a report with header and footer and two details, detail1 and detail2 with two different subreports.
The idea is that header, footer, detail2 should be painted on the first page and if there is space on the page then detail1 and on the next and subsequent page header, detail1 and footer are painted:

          Page 1:
                    header
                    detail1
                    detail2
                    footer
          Page 2 and onwards:
                    header
                    detail1
                    footer

Similarly detail2 may occupy more than one page so it would be painted:

          Page 1:
                    header
                    detail2
                    footer
          Page 2:
                    header
                    detail1
                    detail2
                    footer
          Page 3 and onwards:
                    header
                    detail1
                    footer

Thanks a lot