geoserver - Doing crop coverage with WPS chain in SLD?

I had 2 layers:

custom:Temperature: Point layer.
custom:Region: Polygon layer.

I would like to perform a gs:CropCoverage of the Raster Layer which is the result of gs:BarnesSurface of vector layer 'custom:Temperature' against the FeatureCollection collected from the vector layer 'custom:Region'.

The SLD file is below:

    
         xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
     xmlns="http://www.opengis.net/sld"
     xmlns:ogc="http://www.opengis.net/ogc"
     xmlns:xlink="http://www.w3.org/1999/xlink"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

      
        CropCoverage
        
          
          
            
               
                
                  coverage


                   
                    
                      data   
                    
                    
                      valueAttr
                      TEMP
                    
                    
                      dataLimit

                      2000
                    
                    
                      scale
                      0.05
                    
                    
                      convergence
                      0.2
                    

                    
                      passes
                      3
                    
                    
                      minObservations
                      0.1
                    
                    
                      maxObservationDistance

                      1
                    
                    
                      pixelsPerCell
                      4
                    
                    
                      outputBBOX
                      
                        wms_bbox

                      
                    
                    
                      outputWidth
                      
                        wms_width
                      
                    
                    
                      outputHeight

                      
                        wms_height
                      
                    
                    
                      queryBuffer
                      0.5
                    
                   


                

                
                  cropShape
                   
                    
                      features 
                    
                   
                

              
            
            
              rule1
              
                
                  STATION_GEOMETRY
                
                
                  

                  
                  
                  
                  
                  
                  
                  
                  
                
              

            
          
        
      
    

The data of gs:BarnesSurface should be layer 'custom:Temperature' and feature of gs:CollectGeometries should be layer 'custom:Region'.

How should i set 'data' and 'feature' when i request wms with the SLD above?

.../wms?layers=custom:Temperature,custom:Region&style=CropCoverage&... ?