disclosureBlock on thumbnail is difficult to use (not very MVC)

[connectdotz]

we need to display a detail controller when user tap on the disclosure button. Since the disclosureBlock is defined in thumbnail (model), which doesn't have access to the views JPSThumbnailAnnotationView nor MKMapView and can't be override without changing the thumbnail, what is the best way to deal with this common use case?

can the JPSThumbnailAnnotationView invoke map.delegate's calloutDidTap callback if the block is nil? Otherwise expose the block on JPSThumbnailAnnotationView so we can override it ourselves? thoughts?