GST in MarketPress Confirmation E-mails Not Displaying for Digital Products

When a customer places an order, they are shown a confirmation screen and this has the sub-total, gst, and total.

However, the e-mail that we receive is not displaying the GST. We are using the e-mails as order tickets for our kitchen and it would be a lot easier if it contained this information. I've noticed that if I switch the products on Marketpress to Physical/Tangible products, then it does display the GST, but it also collects addresses (and much more information than we want to bother our customers with -- we do pick up orders only).

Is there a way to make sure the GST is displaying in the e-mail, even when we're using Digital Products in the store? Or is there a way to put a GST or TAX on all orders, no matter what or where they are from?

Thank you.