[TYPO3-project-seminars] modifying the single view hook

[Gregor Hyneck]

Hi,

First of all, I dont't know if this is the best place to ask questions related to PHP programming:
I'd like to modify the hook in pi1/class.tx_seminars_pi1.php:createSingleView()
in order to insert additional fields into the single view.
I have registered the hook in ext_localconf.php:

$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['seminars/pi1/class.tx_seminars_pi1.php']['hooks'][] =
'EXT:seminars_university/pi1/class.tx_seminars_university_pi1.php:tx_seminars_university_pi1';

In my file class.tx_seminars_university_pi1.php, I define the method modifySingleView and call it with a reference paramter to class tx_seminars_pi1 (&$obj):

class tx_seminars_university_pi1{
function modifySingleView(&$obj){
        $obj->setDescriptionMarker(); //example
        }
}

When I want to use a method of class tx_seminars_pi1, I only get a blank screen in FE whick means that this method can't be called or something else is definitely wrong. In order to modify the singleView my way, I have to use methods of tx_seminars_pi1, how can I do that with this hook, what do I wrong?
Thanks in advance,

Best regards,

Gregor Hyneck 
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