Using KeyRemap4Macbook to remap J,K,G,Shift+G in Preview.app

private.xml

<?xml version="1.0"?>
<root>
  <item>
    <name>Enable at only Preview</name>
    <item>
      <name>Use J and K to Up and Down</name>
      <identifier>remap.app_preview_jk2UpDown</identifier>
      <only>PREVIEW</only>
      <autogen>--KeyToKey-- KeyCode::J, KeyCode::CURSOR_DOWN</autogen>
	  <autogen>--KeyToKey-- KeyCode::K, KeyCode::CURSOR_UP</autogen>
    </item>
    <item>
      <name>Use G and Shift+G to Home and END</name>
      <identifier>remap.app_preview_gshiftg2HomeEnd</identifier>
      <only>PREVIEW</only>
      <autogen>--KeyToKey-- KeyCode::G, VK_SHIFT, KeyCode::CURSOR_RIGHT, ModifierFlag::FN</autogen>
      <autogen>--KeyToKey-- KeyCode::G, KeyCode::CURSOR_LEFT, ModifierFlag::FN</autogen>
    </item>
  </item>
</root>