title: Use PHP Code in Custom variable Magento
body: <p>I'm trying to create a new Variable (System -> Custom variable) to use in Email tempalte  (System -> Transactional Emails)
  As you know when we create new custom variable we just only have 2 options :</p>
  
  <pre><code>1) Variable HTML Value
  2) Variable Plain Value
  </code></pre>
  
  <p>How can I use php script like that</p>
  
  <pre><code>&lt;?php
  $a = 1;
  $b = 2;
  echo $a+b;
  ?&gt;
  </code></pre>
  
  <p>By the way, I tried to insert ubsubcriber link to email template </p>
  
  <pre><code>Mage::getModel('newsletter/subscriber')-&gt;loadByEmail($email)-&gt;getUnsubscriptionLink();
  </code></pre>
  
  <p>Because "{{var subscriber.getUnsubscriptionLink()}}" doesn't work , it return NULL,
  Thanks</p>