function set_map_config(perm) {
    fixmystreet.ZOOM_OFFSET = 13;
    fixmystreet.controls = [
        new OpenLayers.Control.ArgParser(),
        new OpenLayers.Control.Navigation(),
        perm,
        new OpenLayers.Control.PanZoomFMS()
    ];
    fixmystreet.map_type = OpenLayers.Layer.Bing;
}

OpenLayers.Layer.Bing = OpenLayers.Class(OpenLayers.Layer.XYZ, {
    initialize: function(name, options) {
        var url = [];
        options = OpenLayers.Util.extend({
            /* Below line added to OSM's file in order to allow minimum zoom level */
            maxResolution: 156543.0339/Math.pow(2, options.zoomOffset || 0),
            numZoomLevels: 18,
            transitionEffect: "resize",
            sphericalMercator: true,
            buffer: 0,
            attribution: "© Microsoft / OS 2010"
        }, options);
        var newArguments = [name, url, options];
        OpenLayers.Layer.XYZ.prototype.initialize.apply(this, newArguments);
    },

    get_quadkey: function(x, y, level) {
        var key = '';
        for (var i = level; i > 0; i--) {
            var digit = 0;
            var mask = 1 << (i - 1);
            if ((x & mask) != 0) {
                digit++;
            }
            if ((y & mask) != 0) {
                digit += 2;
            }
            key += digit;
        }
        return key;
    },

    getURL: function (bounds) {
        var res = this.map.getResolution();
        var x = Math.round((bounds.left - this.maxExtent.left)
            / (res * this.tileSize.w));
        var y = Math.round((this.maxExtent.top - bounds.top)
            / (res * this.tileSize.h));
        var z = this.serverResolutions != null ?
            OpenLayers.Util.indexOf(this.serverResolutions, res) :
            this.map.getZoom() + this.zoomOffset;

        if (z == 16) {
            var url = [
                "http://a.os.openstreetmap.org/sv/${z}/${x}/${y}.png",
                "http://b.os.openstreetmap.org/sv/${z}/${x}/${y}.png",
                "http://c.os.openstreetmap.org/sv/${z}/${x}/${y}.png"
            ];
        } else {
            var url = [
                "http://ecn.t0.tiles.virtualearth.net/tiles/r${id}.png?g=587&productSet=mmOS",
                "http://ecn.t1.tiles.virtualearth.net/tiles/r${id}.png?g=587&productSet=mmOS",
                "http://ecn.t2.tiles.virtualearth.net/tiles/r${id}.png?g=587&productSet=mmOS",
                "http://ecn.t3.tiles.virtualearth.net/tiles/r${id}.png?g=587&productSet=mmOS"
            ];
        }
        var s = '' + x + y + z;
        url = this.selectUrl(s, url);
       
        var id = this.get_quadkey(x, y, z);
        var path = OpenLayers.String.format(url, {'id': id, 'x': x, 'y': y, 'z': z});
        return path;
    },

    CLASS_NAME: "OpenLayers.Layer.Bing"
});