OpenLayers drawing features on clustered layers

I'm having problems adding and moving features on a clustered (wfs) layer. When I add a new feature all the clustered ones disappear from view. Plus much hacking needed to actually save the new feature. Bit of code:

    map = new OpenLayers.Map('map', {
        projection: "EPSG:900913",
        displayProjection: "EPSG:4326",
});
var base = new OpenLayers.Layer.OSM();

filterStrategy = new OpenLayers.Strategy.Filter();

cluster = new OpenLayers.Strategy.Cluster();

protocol = new OpenLayers.Protocol.WFS({
    version: "1.1.0",
    url: "/geoserver/test/wfs",
    featurePrefix: "test",
    featureNS :  "test",
    featureType: "XXXX",
    geometryName: 'geom',
});

wfs = new OpenLayers.Layer.Vector("Vector", {
    projection: "EPSG:4326",
    strategies: [ 
        new OpenLayers.Strategy.Fixed(),
        filterStrategy,
        cluster
    ],
    protocol: protocol,
});

map.addLayers([ base, wfs ]);

drawControl = new OpenLayers.Control.DrawFeature(
    wfs,  OpenLayers.Handler.Point,                  
    { 
         featureAdded: featureAdded,
    }
);

map.addControl( drawControl );

function featureAdded(feature) {
    alert("feature added!");
}

I have similar problems if I want to move a feature.

Any help appreciated

Mini