[graph] edge index in properties

hello,

i tried to implement something like gps with usage of bgl, but i made a
mistake - i am storing graph::traits<>::vertex_desctriptor and
graph_traits<>::edge_descritor in vertex/edge properties as a shortcut
between data and the graph.

this brings a heavy dependency of the property data on the chosen graph
and i am wondering how to assign some numeric vertex/edge index into
these properties (because edge_descriptor is in fact pair of vertices
etc).

my idea is to have adjacency list that is converted into compressed
sparse row graph afterwards.

btw: do you use pointers in your V/E properties? i tried to and now i
quite regret it because of the serialization issues.

many thanks for your attention,

mojmir