title: FuelPHP model's / fieldset / form
body: <p>I am new developing fuelPHP and I have 4 questions about it:</p>
  
  <ol>
  <li><p>I am building a form which uses 2 models, I do this:</p>
  
  <pre><code>$fieldset = Fieldset::forge('register_form');
  $fieldset-&gt;add_model('Model_Ntk_User');
  $fieldset-&gt;add_model('Model_Ntk_Users_Social_Network');
  </code></pre>
  
  <p>But some fields has same name, how can I solve that?. I found a method set_form_fields, but not much info about it.</p></li>
  <li><p>In Yii, in example you can build a model using CActiveRecord (if linked to a table) or CFormModel to build Contact forms in example, how this is done with fuelPHP, model_crud?</p></li>
  <li><p>If I use html form (not build using fieldset) how can I use validation without adding the validation rules in the controller, since they are already set on $_properties in the model?</p></li>
  <li><p>I have created an Observer which adds values to fields like ip_added and date_added, but first is triggered the Observers: Typing and Validation, since those fields are set to "not null" Typing observer throw an exception. So far I have fix it making those fields "null" but I think that is bad idea.</p></li>
  </ol>