title: TYPO3 Extbase extension: Backend FAL Upload fails
body: <p>I have set up an extension with the current extension_builder in TYPO3 6.2.11. 
  FAL File upload in the backend is not working.</p>
  
  <p>extension_builder says that file upload isn't implemented at all in extbase, but as far as I understood (cf <a href="https://github.com/helhum/upload_example" rel="nofollow noreferrer">https://github.com/helhum/upload_example</a>), this is regarding FE upload. Correct? </p>
  
  <p>I only need completely regular BE file upload - select via "Create new relation" or "Select &amp; upload files".</p>
  
  <p>The direct upload fails with "Upload failed! A file with "*" extension is expected!" (or whatever extensions I specify in TCA).</p>
  
  <p>The reference creation works, but the reference is lost after saving.</p>
  
  <p>This screenshot shows the two tries before saving.</p>
  
  <p><img src="https://i.stack.imgur.com/uSAPP.jpg" alt="enter image description here"></p>
  
  <p>And after saving, empty again:</p>
  
  <p><img src="https://i.stack.imgur.com/aM11W.png" alt="enter image description here"></p>
  
  <p><strong>How do I make this work?</strong> Do I have to add extra code to the repo for saving the relation? Or might there be a basic setting missing?</p>
  
  <p>For tt_content, FAL relations and upload work fine.</p>
  
  <p>And: As a workaround, is it possible to use a regular "Pibase" <code>'type' =&gt; 'group','internal_type' =&gt; 'file'</code> field? But how would getters and setters in the model look then? Just like a regular string?</p>
  
  <p>TCA:</p>
  
  <pre><code>    'apprenticeship_document' =&gt; array(
        'exclude' =&gt; 1,
        'label' =&gt; 'LLL:EXT:stellen/Resources/Private/Language/locallang_db.xlf:tx_stellen_domain_model_institution.apprenticeship_document',
        'config' =&gt; \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::getFileFieldTCAConfig(
          'apprenticeshipDocument',
          array('maxitems' =&gt; 1),
          '*'
        ),
      ),
  </code></pre>
  
  <p>Model as created by extension_builder:</p>
  
  <pre><code>/**
   * apprenticeshipDocument
   *
   * @var \TYPO3\CMS\Extbase\Domain\Model\FileReference
   */
  protected $apprenticeshipDocument = NULL;
  
  /**
   * Returns the apprenticeshipDocument
   *
   * @return \TYPO3\CMS\Extbase\Domain\Model\FileReference $apprenticeshipDocument
   */
  public function getApprenticeshipDocument() {
      return $this-&gt;apprenticeshipDocument;
  }
  
  /**
   * Sets the apprenticeshipDocument
   *
   * @param \TYPO3\CMS\Extbase\Domain\Model\FileReference $apprenticeshipDocument
   * @return void
   */
  
  public function setApprenticeshipDocument(\TYPO3\CMS\Extbase\Domain\Model\FileReference $apprenticeshipDocument) {
      $this-&gt;apprenticeshipDocument = $apprenticeshipDocument;
  }
  </code></pre>
  
  <p>I have also tried to use <code>\TYPO3\CMS\Extbase\Persistence\ObjectStorage&lt;\TYPO3\CMS\Extbase\Domain\Model\FileReference&gt;</code> instead of <code>\TYPO3\CMS\Extbase\Domain\Model\FileReference $apprenticeshipDocument</code>, but that doesn't make a difference either.</p>