Not numbered PDF bookmarks from numbered headings of a Word document using Acrobat 6 PDFMaker

I am using Acrobat 6.0 to create PDFs with bookmarks and links using the Adobe PDF (PFDMaker 6.0) MS Word (Word 2000) add-in. I discovered that when the bookmarks in the PDF file are created for headings of the Word file that are numbered using the style formatting option “Bullet and Numbering”, the bookmarks
include only the text part of the heading and not the number part.
I.e. for headings in the Word document like “1. SUMMARY”, “2.INTRODUCTION”, the bookmarks are “SUMMARY”, “INTRODUCTION”, with the numeric part trimmed away.
This happens only when the numbering of the headings is obtained using the formatting option “Bullet and Numbering”, while does not happen when the numeric sequence element is part of the text of the heading.
 
Can you suggest how to obtain that the PDF bookmarks include the numeric part of a heading even if it’s built from a Word heading numbered using the “Bullet and Numbering” formatting option?
 
Many thanks in advance for your precious help!
Best regards,
Armando