Martin,

I'm glad that worked for you.

To remove the Category: from the links, you can edit the Querytree template as such:

<includeonly>
**{{{1}}}|{{#replace:{{{1}}}|Category:|}}
</includeonly>

For this to work, however, you'll need to have the StringFunctions extension installed.
You can find that extension here: http://www.mediawiki.org/wiki/Extension:StringFunctions.

Jennifer