[Boost-users] question about filtered_graph

I am using boost graph library. In order to get a filtered graph, I adopted filtered_graph. I thought it could be used in the same way as adjacency_list. But when I get target and source from an edge of a filtered graph, I realized the target and source function doesn't accept filtered_graph as its argument. How can I get the two terminals of an edge from a filtered_graph then? Thanks for any hints in advance.