code: function(id, geometry, style, featureId) {
          var backgroundStyle = OpenLayers.Util.extend({}, style);
          
          // Set regular style attributes to apply to the background styles.
          backgroundStyle.externalGraphic = backgroundStyle.backgroundGraphic;
          backgroundStyle.graphicXOffset = backgroundStyle.backgroundXOffset;
          backgroundStyle.graphicYOffset = backgroundStyle.backgroundYOffset;
          backgroundStyle.graphicZIndex = backgroundStyle.backgroundGraphicZIndex;
          backgroundStyle.graphicWidth = backgroundStyle.backgroundWidth || backgroundStyle.graphicWidth;
          backgroundStyle.graphicHeight = backgroundStyle.backgroundHeight || backgroundStyle.graphicHeight;
          
          // Erase background styles.
          backgroundStyle.backgroundGraphic = null;
          backgroundStyle.backgroundXOffset = null;
          backgroundStyle.backgroundYOffset = null;
          backgroundStyle.backgroundGraphicZIndex = null;
          
          return this.redrawNode(
              id + this.BACKGROUND_ID_SUFFIX, 
              geometry, 
              backgroundStyle, 
              null
          );
      }
docs: Method: redrawBackgroundNode
  Redraws the node using special 'background' style properties. Basically
  just calls redrawNode(), but instead of directly using the
  'externalGraphic', 'graphicXOffset', 'graphicYOffset', and
  'graphicZIndex' properties directly from the specified 'style'
  parameter, we create a new style object and set those properties
  from the corresponding 'background'-prefixed properties from
  specified 'style' parameter.
  
  Parameters:
  id - {String}
  geometry - {<OpenLayers.Geometry>}
  style - {Object}
  featureId - {String}
  
  Returns:
  {Boolean} true if the complete geometry could be drawn, null if parts of
  the geometry could not be drawn, false otherwise