Watermark option not appearing while exporting Lightroom 4.2

Earlier, while exporting an image, I used to get an option to choose whether I want to add a water mark or not - and other details related to water mark (color, font size, location) were also available in the "custom export" menu.  Now - this option is no longer available.

How and from where can I now add the watermark to my pictures while exporting?