There is an unfortunate obstacle here...
The forum software does allow a .PDF (Acrobat) file to be attached to a post. However, the 40k max file size rule still applies to the attachment.
Unfortunately, most graphic-rich .PDF files are usually always much greater than 40k in size.
The appropriate alternative is to place the file on another server and then provide a link to it within a post.
Ron..send me the .PDF and I'll put ir up on a server to show you what I mean... (attach it to an e-mail to me)