title: CakePHP2 - Default value for input - select with option multiple
body: <p>I have Form input with multiple select options. I am unable to set default values. This is my code:</p>
  
  <pre><code>      &lt;?= $this-&gt;Form-&gt;input('PaymentMethods', array(
            'type' =&gt; 'select',
            'multiple' =&gt; true,
            'label' =&gt; false,
            'options' =&gt; array(
              'cash'=&gt;'cash',
              'invoice'=&gt;'invoice',
              'ax'=&gt;'ax',
              'ca'=&gt;'ca',
              'vi'=&gt;'vi',
              'tp'=&gt;'tp',
              'dc'=&gt;'dc'
            ),
            'default'=&gt;'ax'
        )); ?&gt;
  </code></pre>
  
  <p>How do I set default values for this input with PHP only?</p>