[TYPO3-project-seminars] Problems to call functions via Majix

[Christian Philipp]

Hi there, 

I'm Christian and very impressed by this well designed extension. Good work! 
But I'm having some problems calling functions located in class.tx_seminars_pi1_registrationEditor.php via Typoscript. 
This is my try: 
seats = renderlet:LISTBOX 
seats { 
name = seats 
onchange { 
runat = ajax 
params = seats 
userobj.php ( 
$sRub = $this->oMajixEvent->getParam("seats"); 
return $this->aORenderlets["feuser_data"]->majixSetHTML($this->oParent()->getSeminar()->getAvailablePrices($sRub)); 
) 
.... 

Somehow it must be able to call those functions, but I just don't know how... Does anyone have an idea? 
Thanks a lot! 
c