Namespaces in this file are too complex ?

I need to parse a rather complex xml feed. Problem: I cannot move beyond the gzd-tag in the xml. This tag contains a lot of namespace links:

xmlns="http://standaarden.overheid.nl/sru" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:overheid="http://standaarden.overheid.nl/owms/terms/" xmlns:overheidbm="http://standaarden.overheid.nl/bm/terms/" xmlns:overheidproduct="http://standaarden.overheid.nl/product/terms/" xmlns:overheidrg="http://standaarden.overheid.nl/cvdr/terms/" xmlns:overheidvac="http://standaarden.overheid.nl/vac/terms/" xmlns:overheidvg="http://standaarden.overheid.nl/vergunningen/terms/" xsi:schemaLocation="http://standaarden.overheid.nl/sru gzd.xsd"

Below the xml with more context. But please use the attached file for the complete xml; the xml here is shortened for more easy reference.

For context I use: /searchRetrieveResponse/records/record
That works correctly, because the debugger reports the content of this context correctly.

For a field I want to use: recordData/gzd/originalData/overheidbm:meta/overheidbm:owmskern/dcterms:identifier

But this does not work. The debugger returns an empty value.

However, I tested this in an online testbed: http://www.whitebeam.org/library/guide/TechNotes/xpathtestbed.rhtm
And there the context and field combination work correctly with the attached file.

If I enter only recordData for a field, then it still works: the debugger returns the contents for that tag correctly. But recordData/gzd returns nothing. Somehow the parser cannot pass by the gzd-tag ?

Any ideas ? Did I miss something ? Is it a bug ?