[BGL] Using external edge properties

I have a graph which might change during it's lifetime. I want to attach external properties to this graph. Now, it seems like that in order to be able to attach external properties, I need to have an internal property with edge indices, ie that enumerates the edges. These indices need to be continuous as I gather, since they are used to index for instance a vector of num_edges() elements. Does this mean that I have to re-enumerate all edges if I remove one? This seems to me very cumbersome and also time consuming if the graph is large and changes a lot. Is there another way? Björn Lindberg