RE: Matching nodes in the default namespace

[...snip...]

If your stylesheet doesn't include a namespace declaration for a namespace
that's in the source document, there is no way you'll be able to explicitly
match nodes in that namespace (apart from using a wildcard, such as *).
Remember, whether the source document uses prefixes or not is completely
immaterial in XSLT.  Forget about prefixes and think only about fully
qualified names which consist of a local name and a namespace URI.  How that
fully-qualified name is represented, whether by a default namespace or a
namespace prefix, is immaterial.