RDF addDatasource

Hi,

We're currently dealing with RDF datasources.
We use one RDF for displaying a tree (dont-build-content), and we'd like 
to update and add parts of the tree dynamically.

We use the compositeDatasource to add RDFDatasources, but it does not 
work if the elements in the new datasource were already present in the 
original datasource. We really want the new datasaource to overwrite 
existing parts, I thought the coalesceDuplicateArcs should deal with 
this case, but it is not (maybe the RDF we build does not have the 
required attributes ?)

Thanks for any help.

--
Christian