In Excel, note that selecting the "Convert to PDF" option converts only the selected worksheet(s) ("tabs") - not the entire workbook. To convert an entire Excel workbook to PDF and customize the appearance of the pages, use the Attach Plus print driver:
Select File > Print
Select either "Attach Plus - Save and E-mail PDF" or "Attach Plus - E-mail PDF" from the list of printers, and click Print
This will convert the entire file to PDF, then bring up the Attach Plus dialog to further customize, where you can select the correct pages to attach, etc.