Geowebcache wms cql_filter parameter not working

I am using the geowebcache stadalone to increase the performance, but I can not use cql_filter.

GeoserverWmsUrl: http://localhost:8080/geoserver/ISUPGIS/wms

GeowebcacheWmsUrl: http://localhost:8080/geowebcache/service/wms

        var layer = new OpenLayers.Layer.WMS(
            "layer",
            GeowebcacheWmsUrl,
            { layers: "tora:paths", transparent: true, TILED: 'true', gridSet: "EPSG:99000"},
            { isBaseLayer: false }
        );

        layer.mergeNewParams({'CQL_FILTER': 'id=99'});

If I use GeoserverWmsUrl this filter is working. But GeowebcacheWmsUrl is not working.