OK, after a lot of looking around I found a pdf file in the /company/0/pdf_files/ directory. That file contains all of the test invoices I've created so far in the proper format (displays company header and customer info in an attractive format).
I guess my question now is; how can those pdf invoices be printed from the FrontAcconting interface?
****Edited to Add****
OK, I figured it out. When you create a Direct Invoice don't print it, because it will be in the funky unattractive format. After you are done creating the invoice click Sales-->Inquiries and Reports-->Customer Transaction Inquiry. You will see all orders listed there. In the right column of each order there is a little printer icon. Click on the print icon and a pdf file in the attractive invoice format will display in a new browser window, which you can print.
Note: If the pdf invoice doesn't display when you click the print icon then you will need to install Acrobat Reader (and maybe the browser plugin) in the workstation computer.
I don't mind saying that this seems to be the long way around just to print an invoice. I don't see what it would hurt to have the capability to print a pdf invoice as soon as the invoice is created.