#23 no way to specify namespaces

[Anonymous]

i've got several documents with sections like below
<foxml:xmlContent>
<rdf:RDF xmlns:fedora-rels-ext="info:fedora/fedora-system:def/relations-external#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
...
although the namespace definition is there, for a query like

foxml:xmlContent/rdf:RDF/rdf:Description/fedora-rels-ext:isMemberOf/@rdf:resource

XPath Navigator complains
"XPath Expression evaluation failed :
Prefix must resolve to a namespace: rdf."

there's no way, to either add a namespace somehow or make XPath Navigator use the correct namespace definition.