There's a setting in Config that you might have to adjust to use more than 2 layers. However, the hardware has to Support it or the engine will default back to 2 layers.
You can adjust uv-coords of other layers by using the PolygonManager and by compiling the objects with compile(true, false). But it's a quite expensive operation. I don't recommend to do this frequently. Another option is to use a shader for this.
Bzw: Is this question jPCT or -AE related?