utnik:
Thank you for your reply. Indeed, when I clicked the "Save as PDF" button in the toolbar and made sure Compatibility: is set to PDF 1.5 or PDF 1.6, my logo saves in the pdf file exactly as it is shown on-screen. (5% opacity)
However, when printing, (or displaying a print preview) the image frame displays the graphic at 100% opacity again... So I took a closer look at the settings in the print preview dialog and noticed the first preview setting was set to "PostScript Level 3". I changed this to "PDF" and my transparency immediately displayed at the 5% opacity I selected - as intended.
So I went to the print dialog, and sure enough, the Print Destination dialog box showed, under options, "PostScript Level 3". When I changed this to PDF, my printer output produced the intended 5% opacity! Apparently PostScript Level 3 does not like 5% transparencies (or at least on my laser printer).
Thank you for pointing me in the right direction!