hmm. Let me see if I could offer a little bit from my own experience. PDF files aren't apart of the type of files handled by a browser. That being said no browser really handles pdfs, you can see pdf files in your browser like internet explorer because of an applet. This applet (or mini application) allows you to view the files while still staying in your comfort zone, but to run most applets need another frame or another window. So that means if you want to show PDF files or any other kind of file handled by an applet you will have to load it in a seperate window (or frame) and that might be a little tricky to do but I'm confident it's do-able. Try modifying the code where it shows attached files to load the PDF in a new iframe. This will however open you up to a couple security problems and not all computers (or browsers i should say) have the ability to veiw pdf files in the comfort of their windows (because browsers are user dependent) so you will have to make the decision to proceed if this really is necessary for you. Hope this helps.

Thank you so much for your reply. It´s sharp and clarifier.

But I realize that my message was confusing (sorry!), because I didn´t ask for something to make a pdf document appear in the blog, but the list of attached documents, as I saw in other blogs.
See the image below:
http://irati.pnte.cfnavarra.es/iturrpro/aldizkaria/blogs/media/users/admin/outputlist.jpg

In my blog, even I attach the files, the list of them doesn´t appear.
I´ll be satisfied with the list.

Sorry for the misunderstanding