[TYPO3-mvc] ExtBase concept question about models and passing objects

[Andrea Schmuttermair]

Hi there,

I have a problem with designing ExtBase Models, and I think it is more  
a problem about understanding the concept.

So this is the task:

1) action new -> input form, fills the model: contact
2) action create -> store to database in table contact
    if create is successfull: redirect to process
3) action process

I have security sensitive data in contact from step 1).
In Step 2, I store them to database.
This is how it works right now, I redirect to process. I adding all  
needed data directly in an array:

     /**
      * action create
      *
      * @dontverifyrequesthash
      * @param Tx_MyExt_Domain_Model_Contact $newData
      * @validate $newData Tx_MyExt_Domain_Validator_ContactValidator
      * @return void
      */
     public function createAction($newData) {
         $insert = $this->contactRepository->insertCrypted($newData);
         if ($insert) {
             $this->flashMessageContainer->add('Added contact to  
database successfully.','',t3lib_Flashmessage::OK);

             $this->redirect('process','Contact','myext',array(
                 'firstname' => $newData->getConsumerFirstname(),
                 'lastname' => $newData->getConsumerLastname(),
                 'contactId' => $newData->getContactId(),
                  ));
         } else {
             $this->flashMessageContainer->add('Could not add contact  
to database','',t3lib_Flashmessage::ERROR);
             $this->redirect('new');
         }
     }

If it was pure PHP, I can imagine 2 better solutions:

a) define a new Model "contactSanitized" that can be created from "contact"
function getContactSantizied(){
   $obj = new contactSanitized($this->firstname,$this->lastname,...);
   return $obj;
}

b) remove sensitive Data from Contact, and then pass newData object:
function removeSensitive(){
  $this->bankaccount="";
  ...
}

I tried Nr. b) already, but got an Exception about persistence, even  
the suggested "persistAll" did not work. And I am not sure, if this  
function will really remove sensitive data from the object.

About a) creating a 2nd Model: this will be a model without database  
table, its use is only for holding and passing data.
Now if I place it within Classes/Domain/Model I have no idea what  
ExtBase Magic will do with that model? Will it try to find a a table?  
And how it will be passed in browser as it has no UID?

As you can see, I am not deep enough in the Extbase Model and  
persistance concept to understand and find a good solution. Any hints  
would be great, even if it needs a redesign.

TYPO3 Version: 4.5.25
ExtBase: 1.3.4

Best regards,
Andrea