To be included in business reports (and I don't know where else) you have to assign the category to a schedule C or E tax line item number. To check the tax line assignment open the Category list by either clicking on the Category Icon or go to Tools-Category List or Ctrl+Shift+C. Then select the category and right click on it to Edit it. Click on the Tax Reporting Tab and check the box for Tax related and pick a Schedule C or E:tax line item.
I'm staying on Quicken 2013 Premier for Windows.