how to add water material on a polygon in the czml?

i can use the following code to add a polygon with water material on the globe,but i want to the polygon’s height is changing along with the time, so i use czml to add polygon, but i can’t find the “polygon.material.water” property in the czml content.is there other way to resolve this problem? thanks

part 1:

var watetMe = new Cesium.Material({

fabric : {

type : ‘Water’,

uniforms : {

//specularMap: ‘…/images/earthspec1k.jpg’,

normalMap: ‘Assets/Textures/waterNormalsSmall.jpg’,

frequency: 100000.0,

animationSpeed: 0.06,

amplitude: 1.8

}

}

});

this.viewer.scene.primitives.add(new Cesium.Polygon({

positions : positions,

material : watetMe

}));