Rewrite the LayerDescription.getStyleMap() using OpenLayers.Rule to differentiate cluster from non cluster to mix externalGraphics with cluster circles.
An example is given here :http://dpinte.wordpress.com/2008/11/07/using-openlayers-filters-with-cluster-strategy/
Rewrite the LayerDescription.getStyleMap() using OpenLayers.Rule to differentiate cluster from non cluster to mix externalGraphics with cluster circles.
An example is given here :http://dpinte.wordpress.com/2008/11/07/using-openlayers-filters-with-cluster-strategy/