[Boost-users] how do I access m_property on an edge_descriptor

Hi, How do I access the m_property value of an edge_descriptor. I'm using an undirected graph and I need to get a unique identifier for each edge in the graph. The vertex pair I currently use for edges create two possible identifiers for each edge, but the m_property value of each edge appears unique only I cannot access it. Thanks, any help appreciated. George