https://www.youtube.com/watch?feature=player_embedded&v=cgH6RPM6RVI
The latest product from REX Studios and their first directly supporting FSX:SE is REX Soft Clouds – a new texture set giving a “true volumetric feel” to your virtual water vapour.
The new set includes 512 cloud textures in 16 sets, covering every type you will find in the sim, plus a number of improvements to the visuals such as lightning presentation when inside cloud. It is compatible with FSX DVD, FSX:SE, P3D v1 and P3D v2. To find out more, click here.