Create TextureAtlas in CZML for Billboards ?

Is there a way to create a texture-atlas in CZML for use in CZML billboards?
I want to add billboards from CZML file to Cesium widget, but I want the actual icons (images) to be loaded as "sprites" or like they are loaded from on image when using TextureAtlas.


Not at this time, but it is something we would like to eventually add in the future.