I've set my custom tax summary as such:
<table border="0">
<tbody>
<tr>
<td align="left"></td>
<td align="left"></td>
<td align="left"></td>
<td align="right">Subtotal</td>
<td align="right">{subtotal_net}</td>
</tr>
<tr>
<td align="left"></td>
<td align="left"></td>
<td align="left"></td>
<td align="right">Sales Tax*</td>
<td align="right">{subtotal_tax}</td>
</tr>
<tr>
<td align="left"></td>
<td align="left"></td>
<td align="left"></td>
<td align="right">Shipping*</td>
<td align="right">{shipping_net}</td>
</tr>
<tr>
<td align="left"></td>
<td align="left"></td>
<td align="left"></td>
<td align="right">Total</td>
<td align="right">{total}</td>
</tr>
</tbody>
</table>
But nothing displays properly on the invoice. Attaching an example of the invoice.