It will be nice when the skydome can accept procedural shaders, but it is possible now to get an equivalent result. Just build your procedural shader on a sphere primitive and export the primitive in OBJ format, checking the "convert procedural to texture" option with a 2x1 ratio for the image dimensions. Then open the scene in the properties box, find the texture map you just created, and make it a skydome. This first picture uses only one direct light, with skydome vertical tiling set at 2 for the horizon effect.