title: Custom column for creditmemo in magento
body: <p>I'm using Magento EE 1.14.2.
  I need new column "custom_id" in both creditmemos and invoices. So I made an installer:</p>
  
  <pre><code>$installer = $this;
  $installer-&gt;startSetup();
  $alter = "
   ALTER TABLE sales_flat_invoice ADD COLUMN custom_id VARCHAR(30) UNIQUE COMMENT 'custom increment_id';
   ALTER TABLE sales_flat_invoice_grid ADD COLUMN custom_id VARCHAR(30) UNIQUE COMMENT 'custom increment_id';
  
   ALTER TABLE sales_flat_creditmemo ADD COLUMN custom_id VARCHAR(30) UNIQUE COMMENT 'custom increment_id';
   ALTER TABLE sales_flat_creditmemo_grid ADD COLUMN custom_id VARCHAR(30) UNIQUE COMMENT 'custom increment_id';
   ALTER TABLE sales_flat_creditmemo ADD COLUMN rma_increment_id VARCHAR(255);
   ALTER TABLE sales_flat_creditmemo ADD INDEX (rma_increment_id);
  ";
  $installer-&gt;run($alter);
  
  $installer-&gt;endSetup();
  </code></pre>
  
  <p>When I'm saving invoice like this:</p>
  
  <pre><code>$object-&gt;setCustomId($customId);
  $object-&gt;save();
  </code></pre>
  
  <p>row in table sales_flat_invoice_grid also updates... But when I'm saving a creditmemo in the same way, sales_flat_creditmemo_grid it's not updated.</p>
  
  <p>Any ideas?</p>