Display non-inventory item in webstore cart

This is my first time working with a Site Builder Webstore, and I'm having a problem displaying a non-inventory item in the cart.

The non-inventory item is a Canadian tariff charge that gets added via a Recalc function that runs after the shopper adds items to the cart.  The script uses the items' Handling Charge field to apply an amount to the Canadian Tariff line item.  So, if item 1 has a handling charge of $3 and item 2 has a handling charge of $4, then a third line item is added that is the Canadian Tariff charge of $7.

For the most part, it works.  The tariff charge item is added and is reflected in the Items Total amount of the order, except the line item doesn't show up in the cart on the screen.  It appears to be misleading because all you see is Item 1 and Item 2, but then you see the Items Total that is a higher cost because it includes the Tariff.  Anybody have any idea what I'm missing here?