javascript - How to create folders when exporting OL to KML

I have this function that export all plotted features on my OpenLayers (2.6) map, by using the OpenLayers.Format.KML as follows:

var featuresToExport = [];

for (var i = 0; i < MAP.__layers.length; i++) {
    if (MAP.__layers[i].getVisibility() && MAP.__layers[i].features != null) {
        for(var j = 0; j < MAP.__layers[i].features.length; j++){
            featuresToExport.push(MAP.__layers[i].features[j]);
        }
    }
}

var format = new OpenLayers.Format.KML({
    'maxDepth':10,

    'extractStyles': true,
    'extractAttributes': true,
    'extractTracks': false,
    'internalProjection': MAP.__map.baseLayer.projection,
    'externalProjection': new OpenLayers.Projection("EPSG:4326")
});

var kml = format.write(featuresToExport);

That way, all features are put at the same level on the KML. I would like to be able to arrange them in folders, for example for each layer.

How can I do that? The write function always write the complete KML structure, otherwise I could do something like this:

for (var i = 0; i < MAP.__layers.length; i++) {
    if (MAP.__layers[i].getVisibility() && MAP.__layers[i].features != null) {
        featuresToExport = [];

        kml += "Layer " + i + "";

        for(var j = 0; j < MAP.__layers[i].features.length; j++){
            featuresToExport.push(MAP.__layers[i].features[j]);
        }

        // write this features
        kml += format.write(featuresToExport);
        kml += "";
    }
}

Answer

Ok, so in the absence of a better solution, I'll just cut the parts I want and rearrange the hierarchy.

var kml = "";
    kml += "My exportSome description";
var layerString = "";


// Write features into a KML string
for (var i = 0; i < MAP.__layers.length; i++) {
    if (MAP.__layers[i].getVisibility() && MAP.__layers[i].features != null) {
        featuresToExport = [];

        kml += "Layer " + i + "";

        for(var j = 0; j < MAP.__layers[i].features.length; j++){
            featuresToExport.push(MAP.__layers[i].features[j]);

        }
        // write this features
        layerString = format.write(featuresToExport);
        kml += layerString.match("<\/description>(.*)<\/Folder>")[1];
        kml += "";
    }
}
kml += "";

Edit: Better than that is to use jQuery.parseXML and work with the DOM objects instead of string.

layerString = format.write(featuresToExport);
layerDOM = $.parseXML(layerString);
layerDOM = $(layerDOM).find("Folder")[0];