Thank you I use CUBE for main sky and DOME is for cloud. This is code I have:

type = "skyblue+2.tga";
scale_x = 2.0;
scale_y = 2.0;
flags = DOME | VISIBLE;
layer = 3;
speed_u = 7.0;
speed_v = 8.0;

It work but turn to camera like sprite.