[Typo3] $additional*-arrays @ t3lib_TCEforms

[tuccain]

hi at all,

i've extended the t3lib_TCEforms-class, but unfortunately i cannot add 
some code to following arrays: $additionalCode_pre, $additionalJS_pre, 
$additionalJS_post, $additionalJS_submit. how can i use those arrays?

i need your help! ;-)
tuccain