you can use Universal Emai to edit the email message.
The code to show the shipping is:
<?php echo WA_eCart_DisplayMoney($<your cart name>, $<your cart name>->GetShipping()); ?>
to show the tax:
<?php echo WA_eCart_DisplayMoney($<your cart name>, $<your cart name>->GetTax()); ?>
where <your cart name> is name of your eCart object.