title: multiselect, set default selected values
body: <p>How can I set selected values for a multiselect within my controller?
  This is my code so far</p>
  
  <pre><code>    class Blog_Form_Post extends Zend_Form
      {
          public function init()
          {
      ...
              $this-&gt;addElement('multiselect', 'categories', array(
                  'label'      =&gt; 'Categories:',
                  'required'   =&gt; false,
              )); 
      ...
  
              $form = new Blog_Form_Post();
              $categories = new Blog_Model_DbTable_Categories();
              $categories = $categories-&gt;fetchAll();
              foreach ($categories as $category)
              {
  // Some of the categories needs to selected by default
                  $form-&gt;getElement('categories')-&gt;addMultiOption($category-&gt;ID, $category-&gt;name);
  
  
          } 
  </code></pre>
  
  <p>Edit to be more clear. I am taking the example from Aron Rotteveel</p>
  
  <pre><code>$multi-&gt;setMultiOptions(array(
      'foo' =&gt; 'Foo',
      'bar' =&gt; 'Bar',
      'baz' =&gt; 'Baz',
      'bat' =&gt; 'Bat',
  ));
  </code></pre>
  
  <p>I want Foo and Bar to be selected while Baz and Bat should be unselected when the form is rendered. IE</p>
  
  <pre><code>&lt;select name="categories[]" id="categories" multiple="multiple"&gt;
      &lt;option selected="selected" value="foo"&gt;foo&lt;/option&gt;
      &lt;option selected="selected"value="bar"&gt;bar&lt;/option&gt;
      &lt;option value="baz"&gt;baz&lt;/option&gt;
      &lt;option value="bat"&gt;bat&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>