[TYPO3] Problems with class t3lib_TCEforms

[Christoph Forman]

Hi list,

i am writing a backend extension for some configuration and user
creating stuff. One part of my extension has a formular with some
inputs and one multiple select box for Typo3 Element Browser. And here
is the problem. Generating the box is no problem with an object of
class t3lib_TCEforms. But the Element Browser does not add the clicked
elements to the box. Unfortunately i did not find an adequate tutorial
or documentation for using the class, so i do all the stuff with the
use of the API and try&error. Following functions i call to generate
the Box:

----------- Code Snippet ---------------------------------------------
$tce = t3lib_div::makeInstance('t3lib_TCEforms');
$tce->backPath = $BACK_PATH;
$params = array(
        'size' => 2,
        'dontShowMoveIcons' => 1,
        'autoSizeMax' => 0,
        'maxitems' => 2,
        'style' => " style='width: 150px;'",
        'readOnly' => 0);
$tce->printNeededJS['dbFileIcons'] = 1;
$out.= $tce->printNeededJSFunctions();

$out.= "<form action='".$PHP_SELF ."' method='post' name='editform'
enctype='multipart/form-data'>";
$out.=
$tce->dbFileIcons('pid','db','pages',$loadDB->itemArray,'',$params);
----------- Code Snippet ---------------------------------------------

Neither the delete button nor the add button works...  I don't know
what function i have to call/add to fix that. Can anyone help
me finding my error, please?

Thanks in advance
Christoph Forman