[Typo3] getting typoscript constant values

[Meinte van't Kruis]

Hi folks,

Trying to print predefined constants in my extention... I've defined
the constants in
ext_typoscript_constants.txt:

plugin.tx_extxml_pi1{
# cat=xml_reader/enable/0; type=file; label=xml stuff: tralalala
       xml=fileadmin/xml/test.xml

# cat=xml_reader/enable/1; type=string; label=xml stuff: tralalala
       childnodes=firstchild,firstchild.firstchild
}

Now the Pibase class is trying to print them, but it shows no values:

       function main($content,$conf)   {
               return var_dump($conf);
       }

Am I doing something wrong here?

Thx