How to Add a Line Item With Tax Included

[dempstert]

When I create an invoice manually, I can include tax in Line items.
After that the subtotal tax is also included.

When I create an invoice with the API, it doesnt seem possible to do this:

I have tried:

1. When creating a XeroInvoice Object, adding line_amount_types=LineAmountTypes.INCLUSIVE
2. Including the tax specifically on a Line Item

What can I do - it doesn't work either way