[graph-tool] loading in graphs, property map issue

I have created a graph in xml format and saved this graph. When I go to load in graph, I am successful but the property maps are no longer populated as they were when I created the graph. All bool values go to 0, all ints go to 0 and all strings go to '' Any idea why this is happening and how I can successfully load in both the graph and the populated property maps? Thanks John Hirdt