Kim, I have read that planting the seed when it is very fresh and just turning red and before it gets hard, works very well, especially if you happen to catch them at that stage.
If not pouring boiling water over the seed in a cup and let it soak in it overnight can work, it works with many of the hard seeds, but do not boil the seeds, that will kill them.
Good luck with your seed, Texas Mountain Laurels can be difficult to start, but they are so very beautiful!!
They are also one of our few native evergreen trees and they are very much worth the effort.