[xsl] with or without namespace

[ac <ac@xxxxxxxxxxxxx>]

Hi,

I have a xslt2 stylesheet that transforms to (x)html, an XML document 
type that comes in two flavors, both with the same "local-name" 
elements, but with or without namespace.

For example, either:

... xmlns:xx="aaa.cc">
<xx:a>
<xx:b>bla</xx:b>
</xx:a>
...

or

...>
<a>
<b>bla</b>
</a>
...

To process these elements irrespective of their namespace, I can use 
expressions like
*[local-name(.) = "a"] and *[local-name(.) = "b"]
all through the stylesheet but, in the stylesheet, I would much rather 
map everything to the same namespace (possibly to default- or 
no-namespace) and either use a single prefix, or better still, no 
prefix, all over the stylesheet, to refer to all or any of these elements.
/xx:a, /xx:b, or /a , /b, for example
What would be the best way to declare the stylesheet namespaces to 
achieve this, if possible?

Thank you,
ac