Displaying PDFs "in-line"

[pjbw]

Whenever I import a PDF I can get its path (a string of ?'s) to either appear as a child item under my context item in Data Explorer or as a child item in Imported Items. The Adobe page appears Ok in the Details pane when I click on the child item. My Data Explorer pane is going to get very big (from experience with Ecco) and I don't want it cluttered with child path items as happens with Ecco
However, if I import an email from Thunderbird its content appears in the Details pane as soon as I click on the context item in Data Explorer - perfect!. Is it possible to get PDF's to appear like this, and if so how?
Is it to do with the Document, URL attribute? This is blank when I try to import a PDF file and has a value 'email|1.eml' after I have imported an email (only 1 so far).