title: Symfony form not honoring set defaults
body: <p>I have a pretty simple form with some fields from a doctrine model.</p>
  
  <pre><code>$this-&gt;widgetSchema['fields'] = new sfWidgetFormDoctrineChoice(array(
    'model'          =&gt; 'FieldModel',
    'expanded'       =&gt; true,
    'multiple'       =&gt; true,));
  
  $this-&gt;validatorSchema['fields'] = new sfValidatorDoctrineChoice(array(
    'model'    =&gt; 'FieldModel',
    'multiple' =&gt; true,));
  </code></pre>
  
  <p>The fields are rendered in the form as checkboxes and I'm able to check and save correctly. This 'fields'-field is converted to a json-structure and saved to the database as text. So far so good.</p>
  
  <p>NOTE: The field 'fields' is stored as TEXT in the database, but the user should be able to select values from a list of checkboxes.</p>
  
  <p>The problem arise when I want to have some of the checkboxes checked by default.</p>
  
  <p>I tried to do:</p>
  
  <pre><code>$this-&gt;setDefault('fields', array('key1','key2','key3'));
  </code></pre>
  
  <p>Where 'keyX' correspond to the actual value of the primary key (string) for Field in the database.</p>
  
  <p>If I do a</p>
  
  <pre><code>$this-&gt;getDefault('fields');
  </code></pre>
  
  <p>I get back exactly what I put in previously.</p>
  
  <p>However, symfony is not outputing any of the checkboxes as checked. I have even tried to remove both the 'expanded' and 'multiple' options to the choice-widget so I get a simple SELECT-box and the provide only one value as default selected.</p>
  
  <p>Setting default values for other widgets (text-inputs, choice, etc) work.</p>
  
  <p>Btw; The Field-model is i18n. Don't know if that matters here, since both storing / retrieving works as expected.</p>
  
  <p>Also; the form is rendered as part of another form by means of include_partial(). Can that sabotage anything? In the 'parent' form class:</p>
  
  <pre><code>$this-&gt;embedRelation('TheRelationThatBugsMe');
  </code></pre>
  
  <p>And then in the _form.php for the 'parent':</p>
  
  <pre><code>include_partial('the_relation_that_bugs_me/form', array('form' =&gt; $form['TheRelationThatBugsMe']));
  </code></pre>
  
  <p>Does anyone have an idea where I might have gone wrong, or at least can give me some pointers as to where I should start digging?</p>
  
  <p><strong>[UPDATE]</strong></p>
  
  <p>If I create a new field in the form 'fields2' (that does not exist as a field in the database) and use <em>the exact same</em> code to create widget, validator and set defaults, then the defaults are rendered correctly. How come it doesn't work setting defaults for a field mapped to a column in the database?</p>