title: ClassRegistry::init not picking up datetime format from within datasource
body: <pre><code>&lt;?php
  class PluginModel extends PluginAppModel {
    public function hello(){
      $anotherModel =&amp; ClassRegistry::init('Plugin.PluginAnotherModel');
  
      $this-&gt;read();
  
      $db =&amp; ConnectionManager::getDataSource($this-&gt;useDbConfig);
      $db-&gt;begin($this);
  
      $anotherModel-&gt;create(array('AnotherModel' =&gt; $this-&gt;data['PluginModel']));
      $anotherModel-&gt;save();
  
      $db-&gt;commit($this);
    }
  }
  ?&gt;
  </code></pre>
  
  <p>This script is calling another model using the ClassRegistry::init() function. Grabbing the data from the current model and putting it into the create() on the other model initiated.
  When it tries to save I get a SqlServer error converting char to datetime.
  When I debug the data it shows the INSERT datetime format as 'Y-m-d' but in my app/model/datasource/Sqlserver.php I have specified datetime = 'Ymd'.</p>
  
  <p>Why is the datetime format not being picked up? It works as expected on a normal model save, but not when I call another model in with the ClassRegistry::init function?</p>
  
  <p>I have a work around of looping through the dataset before save to convert any datetime fields into the 'Ymd', but this does not sound like the right way of doing it?</p>
  
  <p>Thanks.</p>