I'll specify my thought. UNA has the alert system which means the places with the code like

bx_alert($this->getName(), 'profile_created', 0, 0, array('override_result' => &$mixed, 'remote_profile_info' => $aProfileInfo));

Those callings are everywhere in UNA. So it means to add the processing of the necessary event you may just add the proper handler for it. The alerts handlers are introduced via MySQL commands like Dolphin connect has for example:

INSERT INTO `sys_alerts_handlers` SET `name` = 'bx_dolcon', `class` = 'BxDolConAlerts', `file` = 'modules/boonex/dolphin_connect/classes/BxDolConAlerts.php';

SET @iHandlerId := (SELECT `id` FROM `sys_alerts_handlers`  WHERE `name` = 'bx_dolcon');

INSERT INTO `sys_alerts` (`unit`, `action`, `handler_id`) VALUES

('account', 'logout', @iHandlerId),

('profile', 'delete', @iHandlerId),

('profile', 'add', @iHandlerId);

So when an event like profile add or delete happen then it would be processed with the handlers from modules/boonex/dolphin_connect/classes/BxDolConAlerts.php too. 

So it is the most proper solution for UNA.

But you may insert the RAW block with your given HTML / Javascript code and place it on the profile's creation page and bound the submit "AusfГјhren" button with UNA "Submit" there. On a quick look, the button in your example has the submit_form() function's call onclick. So it should be added to our button too. 

Hope I could explain the possible ways and challenges :-)