Google maps v3: clustering with custom markers

I'm trying to use MarkerClusterer to clusterize the markers on my map. The problem is that I'm not using default markers (google.maps.Marker), but instead a custom class which hinerits from google.maps.OverlayView. Unfortunately it seems that the library has been developed assuming the use of basic markers, in fact I get errors because my class does not implement methods defined in google.maps.Marker. Is it possible to use the MarkerClusterer by keeping my custom markers?

EDIT: it was a lot easier than I expected, I solved by implementing 2 methods in my custom class:

setVisible() and getPosition()

in order to help others the following is my complete interface (without full implementation):

BFPushpin = function(config) 
{
    this.setMap(config.map);
    this.set("position", config.position);
    // other settings...
};

// my class extends google.maps.OverlayView
BFPushpin.prototype = new google.maps.OverlayView();

BFPushpin.prototype.getBounds = function() 
{
    return new google.maps.LatLngBounds(this.position, this.position); 
};

BFPushpin.prototype.getPoint = function() 
{
    var bounds = this.getBounds();
    var projection = this.getProjection();
    var sw = projection.fromLatLngToDivPixel(bounds.getSouthWest());  
        var ne = projection.fromLatLngToDivPixel(bounds.getNorthEast()); 

    return new google.maps.Point(sw.x, ne.y);
};

BFPushpin.prototype.getSuperContainer = function()
{
    var panes = this.getPanes();
    return jQuery(panes ? panes.overlayImage : "");
};

BFPushpin.prototype.getContainer = function()
{
    // return inner container
};

BFPushpin.prototype._generatePopupContent = function()
{
    // return markup for the popupwindow
};

BFPushpin.prototype._addListeners