[TYPO3-calendar] How to extend FE-Editing with an own textarea field? cal 1.5.1

[Andrea Moroni]

Hi,
I have extended CAL some years ago with a textarea field :

create_event.tx_am_printtext_stdWrap{
   dataWrap = <p><label for="tx_am_printtext">Kurztext 
Druck###TX_AM_PRINTTEXT_REQUIRED###:</label><textarea 
name="tx_cal_controller[tx_am_printtext]" cols="50" 
rows="10">|</textarea></p>
   // Disable htmlSpecialChars, if you are using the RTE
         #htmlSpecialChars = 1
      }

now this seems not to work anymore...
Can someone give me please a hit what is wrong?

kind regards, Andrea