Route-Me: Alpstein fork - Customize cluster icon and display cluster count

I am using Route-Me: Alpstein fork for developing an iOS app. The original Route-Me/Mapbox code had an option to customize the cluster icon and also the the cluster count. I've been looking for a way to do this with the Route-Me: Alpstein fork.

Something similar to this:

- (RMMapLayer *)mapView:(RMMapView *)mapView layerForAnnotation:(RMAnnotation *)annotation
{
    if (annotation.isUserLocationAnnotation)
        return nil;

    RMMapLayer *layer = nil;

    if (annotation.isClusterAnnotation)
    {
        layer = [[RMMarker alloc] initWithUIImage:[UIImage imageNamed:@"circle.png"]];

        layer.opacity = 0.75;

        layer.bounds = CGRectMake(0, 0, 75, 75);

        [(RMMarker *)layer setTextForegroundColor:[UIColor whiteColor]];

        [(RMMarker *)layer changeLabelUsingText:[NSString stringWithFormat:@"%i", [annotation.clusteredAnnotations count]]];
    }
    else
    {
        layer = [[RMMarker alloc] initWithMapboxMarkerImage];
    }

    return layer;
}

I cannot see 'isClusterAnnotation' defined anywhere in the source. How can I achieve the same results using the Route-Me: Alpstein fork? Any help would be greatly appreciated.

In my project I used the following, inside the mapView:layerForAnnotation: method of the map delegate:

if ([annotation.annotationType isEqualToString:@"RMClusterAnnotation"]) {        
    UIImage *clusterImage = [UIImage imageNamed:@"foo.png"];
    RMMarker *newMarker = [[RMMarker alloc] initWithUIImage:clusterImage];

    // this is how I managed to count the annotations inside a cluster
    NSInteger annotationsInCluster = [((RMQuadTreeNode *)annotation.userInfo).annotations count];

    // you can add a label to the annotation with the number of clustered annotations
    [newMarker changeLabelUsingText: [NSString stringWithFormat:@"%i", annotationsInCluster]];        
    return newMarker;
}

Hope this works for you!