I just saved it for situation like this 
I call a nesting box, the area within the tank I prepare for my female to lay in. I usually don't use a box at all. I place a brick (normal rectangular) all the way on the left back wall, and another all the left side, at right angles to it...this leaves a space in the middle of the two bricks to hold about 3" of sand. When you do this, you wil find the sand will not be held back in the front. I simply add a vertical flat rock to a portion of the front to hold the sand in. I then dampen the sand, and mix it with my hands until it is damp throughout. Not dripping wet, with standing water, but damp enough to clump when squeezed. I acually mix it very similar to my geckos moisture consistency. After dampening the sand, I place a large flat rock, or terre-cotte flower pot base over the area.
Make sure to leave a noticable entrance into the area. When she gets closer to laying time, start checking the area. When she lays, she will be noticable skinny...Scary skinny
Don't worry, she will be ready to resume eating again soon. I forgot to mention...a good sign she is nearing the time to lay, is her decrease in appetite. She will decrease eating, then stop...at the same time, she will start digging more often, or hanging out in the prepared area. I don't worry too much about temps of the area, since I will move them ASAP after she lays them. I have found, if laid on top of a under-tank heater, the eggs will often stick to the bottom. Under the rock or dish, it protects them from too much heat, since they will be buried anyway. I usually have my egg laying area beneath one side of the tank, under the incandescent. The rock on top gets pretty warm, but I highly doubt the temp of the sand gets very warm at all.
For the egg box used in incubation, I use Perlite as a medium. I started using Perlite, because I can't find Vermiculite around here anymore. I put about 3" of Perlite into a deli-cup container. I add water until it is all moist. The material is quite different from Vermiculite, as it will not feel very soft/wet. The best feature of the product, is you will be able to see cleary the water level in the deli-cup. I wet it evenly, then keep the water level at least 1" below the bottom of the eggs. You can then watch the level, and add more water as needed. Very cool feature. Hope this helps you out.