in universal email, don't select the option to create a file for the email.
instead, click the DW Edit icon to open a dreamweaver page for designing the email body.
add a cart display manager to the page, and select the email friendly display type to show the cart information.
use the "eCart_checkoutForm_" bindings to add information such as billing and shipping information to the email body, when you save the page, it will be converted to the Universal Email body.