How to add Button to userLocation callout??????

[Lfan]

Hey guys,
how can we display a DisclosureButton in the userLocation (the blue dot) callout like the Apple Maps app does ?
Now I just can change its title and subtitle, but I hope to provide custom callout views. Therefore, if I click the blue dot, it can display a button besides only title and subtitle, in this way, when I click the button, it can guide me to another View.
I returned MKAnnotationView in viewForAnnotation when annotation == self.mapView.userLocation , however, the callout can display updated title and subtitle, cannot show the button I added.
I really really need this function, desire any help and suggestion!!!!!
Thank you very much in advance!!!!!!
Best Regards!