serialized form of XML using xslt 1.0

Given:

<foo xmlns="aaa">
  <bar xmlns="">
    <bbb/>
  </bar>
  <baz/>
</foo>

What is the XSLT 1.0 way to create that exactly output as a string -
I'm struggling to think how to handle the namespaces with out the
functions from xpath 2.0.

For example, how do you avoid outputting xmlns="" for <bbb/>  ?

thanks in advance,

-- 
Andrew Welch
http://andrewjwelch.com