Change page orientation from landscape to portrait after conversion OTF>PDF

Dear all,

   I have a smartform with this structure:

   first page: portrait (max 1 page)

   next page: portrait ("n" pages)

   last page: landscape ("n" pages).

   In order to printing and sending this documet I must extract the spool (in PDF format) into a file on application server. This is a special format (.MPX) that can be used from POSTEL (italina service for print and send document by postal service). The format MPX is  a XML document that contain one or more PDF document BASE64.

   My Problem: the PDF cannot include page in landscape format, because not supported by printing systems. I would like to change orientation on last pages with out change the layout orientation in order to create a PDF with only portrait pages (DINA4 210mm x 297mm). In this mode last pages should be in portrait format but with a layout that can be read as a landscape page.

   Thanks in advance for any information,

      Mauro Danzo