Expand/Collapse all the Bookmarks in a PDF file

Hi,

This is my first message on the board :-)

I work with very large PDF files (i.e 2000 pages, 700 bookmarks on 5 or 6 levels!) and I'm looking for a script (Acrobat 9 Pro) allowing to expand/collapse all the bookmarks in a PDF file.

Thanks in advance for your valuable help,

Cheers

Antonella