I'm doing this in Cataclysm but it'll work in WoTLK as well. This is a video I made for someone that goes by the handle jbr373 , The map I'm using is also his however it's upconverted to Cataclysm. In WoTLK you can disable specular lighting to avoid the bright green landscape when you don't have a specular map with your tiles. In Cataclysm and up you can't so You have to make them.
♠ BLP Converter: http://www.wowinterface.com/download...Converter.html
♠ BLPView: http://www.wowinterface.com/download...0-BLPView.html
This method would just make the overall texture be a bit shiny in the sunlight, however if you wanted to have it so the rocks and various little pits in the texture were what had a glare, you'd have to use a level and layer effect to get that which can take time and a lot of back and forth converting and re-editing.
But the simple method should get it done for the most part.