title: Multiselect prodct's attribute
body: <p>I have created a new multi select type attribute from admin in magento using <strong>manage attribute</strong> section and used back end source model for label and  value.</p>
  
  <p>Now when I export the product csv from admin using export all data profile than my multi select attribute shows blank. i want to show selected value in csv.</p>
  
  <p><strong>My source model code:</strong></p>
  
  <pre><code>&lt;?php
      class CityVal_City_Model_Product_Attribute_Unit extends Mage_Eav_Model_Entity_Attribute_Source_Abstract
      {
        public function getAllOptions()
        {
          $connection = Mage::getModel('core/resource')-&gt;getConnection('core_read');
          $sql = 'SELECT  city_id,city_name FROM cities';
          $orders = $connection-&gt;fetchAll($sql);
          foreach($orders as $ord)
          {
              $customerArr[] = array(
                             'value' =&gt; $ord['city_id'],
                             'label' =&gt; $ord['city_name'],
                              );
          }
          if (!$this-&gt;_options) {
              $this-&gt;_options = $customerArr;
          }
          return $this-&gt;_options;
        }
      }
      ?&gt;
  </code></pre>
  
  <p><strong>After foreach we have value in  multi select city drop down in admin. i am unale to post image otherwise,  i post a image</strong></p>