Here's what I've just done which may help you...
I've only got one 'option' which is the PDF so I just changed
modules/Extra_Fields/product.tpl
to the following
Code:
{section name=field loop=$extra_fields}
{if $extra_fields[field].active eq "Y" && $extra_fields[field].field_value}
<TR><TD width="30%">
Download PDF:
</TD><TD>
<a href="PDF/{$extra_fields[field].field_value}.pdf">
[img]{$ImagesDir}/pdf.gif[/img]</a>
</TD>
</TR>
{/if}
{/section}
My one option in the add product page is a text box for the client to put the name of the PDF file in (no file suffix). I upload all the his PDFs to /PDF and they appear for a product that has an associated PDF.