View table in dynamically populated hidden field

Hi,

I've set up a hidden field in my form that is dynamically populated by the following shortcode in my functions.php file and using the parameter "cart" :

add_filter('gform_field_value_cart', 'populate_cart');
function populate_cart($value){
    return do_shortcode("[cart mode="read"]");
}

The [cart mode='read'] shortcode is supposed to display a table with the cart's contents (products, prices, total, etc.), but for some reason all of the table formatting is lost in the email.... The cart's contents are all there, but they are all displayed on separate lines and have several blank lines in between items, which creates a very long email that cannot be forwarded to clients.

Is there any way I can retain the original formatting of the shortcode?

Thanks,

Hi Chris,
It is a Cart66 shortcode, but the email is coming from Gravity Forms.
In an ideal world, I would be using Cart66 with offline payments for my shopping cart, but Cart66 does not allow you to customize the "Checkout" page, and unfortunately there is a lot of other information that I need to gather. So, rather than have the checkout completed by Cart66, I would like to pass the contents of the cart to a hidden field in a Gravity form, which would allow me to collect all of the information that I need. When the user hits "submit", the shopping cart contents and all of the other information in the form are sent to me via Gravity forms.
The function above works, but I was hoping there would be a way to have the field show up in a nice table format. It seems that the html tags are lost somewhere along the way.
Hope this explains more, let me know if you need any further information.
Thanks in advance.