I don't know if this is covered already but I wouldn't doubt it given it's simplicity. 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.
Links:
♠ BLP Converter: BLPConverter : WoW Tools & Utilities : World of Warcraft AddOns
♠ BLPView: BLPView : Developer Utilities : World of Warcraft AddOns
♠ Map I'm Using: http://www.ownedcore.com/forums/worl...ing-woods.html ([World Building] The Sleeping Woods)
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.