Step 2:Open up the model in your modeling program of choice and fill in the "gaps" in the circle. Save the model and reimport.
Step 3:Import back into HMT.
Step 4:Go to the [bitm] tag and find sky/clear afternooon/bitmaps/cloud mask and save that DDS texture. If you are using MS paint, cover the whole picture white, if you are using photoshop, go to the alpha channel and color that white. Now go ahead and save that as a DXT 3 and reimport
Step 5:You're done! This is what you should get:

NOTE:This pic was a rough 30 second job and I already had the actual clouds skinned to my liking. To edit the actual cloud color you must edit sky/clouds/detail puffy light or something alnog those lines.