Xerces XS*, namespace prefixes and XSIDCDefinition string selector

[S ML]

Hello, I use the Xerces XS* classes to parse and get the definition of
an XML schema. I don't seem to find a way to get the namespace prefixes
using this framework and I read somewhere that the reason for that is
possibly because, the same namespace URI can have multiple prefixes.
But the problem I am facing is, the xpath definition specified for key,
keyref and unique elements use the namespace prefixes and these are not
converted to the namespace uri representation. So, I don't see a means
of identifying which element declarations the xpath actually refer to.
Any ideas how I can get around this problem?