title: How do I access images (for document icons) in an asset catalog in the Xcode 5 product preference editor
body: <p>I think I'm literally on the last step before submitting a new Mac app, and I've been banging my head against a wall for the past few hours on what I think should be really, really easy.</p>
  
  <p>I've designed document icons for the two different  types of icons my app creates and works with. I created a new "Icon" in Images.xcassets, and dropped the appropriate files into the drop zones.</p>
  
  <p>In the product editor -> Info, I go to where the document type information is, but when I try to enter in the icon name in the "icon" field of either the Document Types or Exported UTI section, the icon image just turns into a question mark—no options show up in the drop down menus for icons.</p>
  
  <p>How do I get the images/icons in the asset catalog to show up in the editor? Alternatively, if I was going to enter that manually into the plist, what sort of format would I use to reference an Icon file from the asset catalog?</p>
  
  <p>I know I'm probably missing an easy step here, but I can't see it!</p>