Copying Namespace Nodes

Hello,

I have an element I want to copy and in the source it looks like this:

<a:elem
  xmlns:a="example.com/ns/a"
  xsi:type="nsc:foo"
  xmlns:nsc="example.com/ns/sensitive"
  xmlns:b="example.com/ns/b"
  xmlns:c="example.com/ns/c"
  ...
  xmlns:z="example.com/ns/z">info</a:elem>

What I want to achieve at the same time:

1) Keep the namespace declaration for the namespace sensitive content of
the xsi:type attribute (with prefix nsc).

2) Get rid of all namespace declarations that are not needed here (prefix
b, c, ..., z) and that clutter up my result document.


If I use copy-of with copy-namespaces set to 'no' the declaration for
namespace sensitive content will be lost. If I say 'yes' everything stays
the same. So is there a short way I have not seen yet or is the solution
some verbose template? :)

Thanks for help,
Heiko