Custom Field bind to email

Hi,

I'm trying to add a custom field to my checkout page in eCart 4. I was able to add this select menu titled "howDidYouHear". I also validated it and it works perfectly. The problem is I can't get it to show up in the email. I think the problem is on the confirm page where I can't get it to show up under the ecart_checkout_form. I manual pasted the code from my checkout page into the confirm so it reads like this:

<p class="eC_OrderInfo"><span class="eC_OrderInfoLabel">Howdid I hear about Calmer, Easier, Happier Parenting:</span>**<?php echo((isset($_POST["howDidYouHear"]))?$_POST["howDidYouHear"]:"") ?></p>

This works in that it shows up on the confirm page perfectly. But I don't see the server behavior in DW and don't know how to get it there. In the WAUE_confirm_2.php page, I put this code (which doesn't work):

$MailBody = $MailBody . ((isset($_SESSION['howDidYouHear']))?$_SESSION['howDidYouHear']:"");

What am I missing?