setting canShowCallOut = NO for current location annotation, iPhone

I am using custom call out (title and subtitle)for Current location icon. I tried following to disable default annotation but it does not work.

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
    NSLog(@"viewForAnnotation");
    if ([annotation isKindOfClass:[MKUserLocation class]])
    {
        MKAnnotationView *userLocationView = [mapView viewForAnnotation:annotation];
        userLocationView.canShowCallout = NO;
        NSLog(@"[annotation isKindOfClass:[MKUserLocation class]");
        return nil;
    }

}

Only way it works is

-(void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)ann
{
    if([ann.annotation isKindOfClass:[MKUserLocation class]] )
    {
       [mymap deselectAnnotation:ann.annotation animated:NO];
    }
}

But it lags sometimes. Is there other way do disable default callout view for current location annotation? Any help will be appreciated.

To get this done one need to get reference of current location MKAnnotationView. One can get this reference anywhere but it is better to get it as soon as user location is determined.

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation 
{
 MKAnnotationView* annotationView = [mapView viewForAnnotation:userLocation];
annotationView.canShowCallout = NO;

}

Or use following method

 - (void)mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views {
MKAnnotationView *aV; 
     for (aV in views) {
            if ([aV.annotation isKindOfClass:[MKUserLocation class]]) {
                MKAnnotationView* annotationView = aV;
                 annotationView.canShowCallout = NO;

            }
    }

and if want to change in canShowCallout property in runtime then one can use following

for (AnnotationClass* annotation in mapView.annotations) 
    {
        if([annotation isKindOfClass:[MKUserLocation class]] )
        {
             MKAnnotationView* annotationView = [mapView viewForAnnotation:annotation];
             annotationView.canShowCallout = NO;
        }
    }