[TYPO3-calendar] hook to substitute custom marker

[Martin Keller]

Dear list,
to bring in custom values to a create event form, I extended 
create_event.tmpl with a line like

<input type="hidden" name="tx_cal_controller[refpid]" value="###REFPID###">

Then I created a createEventClass-hook called "preCreateEventRendering". 
This hook is called with &$obj, $getDate and $pidList. I studied &$obj 
to find any template or marker stuff to manipulate, but there seems to 
be nothing useful in there.

How can I replace ###REFPID### in the form with my value in the hook?
Is this hook the right place to look for?

Lateron, I plan to hand it over to confirm_event and save_event, where I 
can store the custom values to DB. This question is related to the 
thread "flexible saveEventToPid? 13.05.2011 16:03"

Any clue?
Martin