Send Delivery Status Notification Action - explanation not visible or not send?

Hello

I have trouble enabling Status Notification Action with explanation. (SMG version 10.5.4-4, Exchange 2010 as internal mail server)

I test new Spam Policy (Outbound) with followings Actions:

1. Prepend subject line with "[Spam test]"
2. Send a Delivery Status Notification with explanation "Cant send a SPAM message..."
3. Forward the message to admin_email@..."
4. Hold message in Spam Quarantine

When I send a test SPAM message a notification is send to me, but I'm not see a explanation in this message.

How can I configure to send properly DSN mail with explanation configured?

Thanks for reply.