transition effects

Hi,

 I wanted to make slides compatible with acrobat 1.5 standard. The 
reason behind in doing so is to
exploit new transition effects available. However, I  found  that  
although my initial pdf file
(created by  pdflatex  with \pdfoptionpdfminorversion 5 )  is of type 
PDF-1.5, the post-processing
afterwards makes it PDF-1.3.  How to resolve this issue?

Purnendu