after one month of work i have finnally finnish the PDF and all file upload via admin for product_info page.
for version 2.3.x
i have reduce script at his more simple expression to ability of anyone to modify code and show it if not null anywhere it the catalog.
at this time i have only put a link in product info.php page to see the file who have been upload in admin ,
but it can be modify to be put in any code like flashvar or swf etc...
with this tag" $product_info['products_fileupload'] or $pInfo->products_pdfupload "
this add on have been test with 11 others addon install at the same time without any error, (SQL or Php)
if you have any question it will be a pleasure to help you to resolve your problem..