[TYPO3-core] Problem with checkDataSubmission Hook from tslib_fe

[Stefan Kruse]

Hi,
i would make a usertracking. Therefore i have made an extension like "Login User Tracking". But we need more things to track. Now i would like to register a hook to track the logins and page clicks. In the "Login User Tracking" the Hook was registered like:
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['checkDataSubmission'][$_EXTKEY] = 'EXT:' . $_EXTKEY . '/class.tx_loginusertrack_tsfehook.php:tx_loginusertrack_tsfehook';
But this doesnt work anymore. Why is it so? 

We use Typo3 4.7.5. At the moment we cant make an update. 

Could somebody tell how to register the hook correct in Typo3 4.7.5?
Thanks a lot, Stefan