[TYPO3] includeList in catmenu

[luca]

I'm quite new to typo3 and I got stuck on building a catmenu to navigate 
the news...is there anybody who can give me a hint on how to solve this?

I have installed tt_news 2.2.24 on a TYPO3 Ver. 4.2.1 clean installation.

I have tried to control the CATMENU categories using  excludeList as 
stated on the current online manual
http://typo3.org/documentation/document-library/extension-manuals/tt_news/2.5.0/view/1/7/#id2931185

plugin.tt_news {
     displayCatMenu.excludeList = 1,2
     displayCatMenu.mode = nestedWraps
}

Although I followed  (I think) the suggested setup, my catmenu still 
displays all categories. How can I control which categories display in 
the catmenu?

Luca