How do I send specific information to the payment page?

Ray,
I have placed the following code on the confirm.php page:

<input type="hidden" name="x_life_number" id="x_life_number" value="<?php echo((isset($_POST["life_number"]))?$_POST["life_number"]:"") ?>"
/>

That is where the code is to be placed, correct? It says hidden, so I'm assuming that it gets sent directly to the e-mail (supremehqmoc@lotcs.org) that's listed on the page and doesn't show up on the payment form page. If this information goes directly to that e-mail, then that's awesome! That way my boss can check if the end user is actually a life member or not. Also, is the payment form page generated from e_cart or is it actually the Authorize.net payment form page? I went into our Authorize.net account and checked to see if there is a way to add the life member number there on the virtual terminal. There is not. It seems to be hardwired for just specific blocks of information. Thanks in advance for your help and patience!
Have a nice day, eh?
All the best,