OK, this is what I have come up with.
To get the shipment cost WITHOUT TAX, I had to detract the tax amount (which is 21% here in Italy) by dividing by 1.21. However, I would prefer to put in the variable that represents the tax amount instead of hard-coding it into the php file. Is there such a variable?
In the Admin email (order_admin_notification.html.php):
Shipment cost WITHOUT TAX:
echo '<tr><td colspan="4" style="text-align:right">'.JText::_('HIKASHOP_SHIPPING_METHOD').' : '.$currencyHelper->format($data->order_shipping_price/1.21,$data->order_currency_id).'</td></tr>';
Total TAX (items + shipping):
echo '<tr><td colspan="4" style="text-align:right">'.JText::sprintf('TOTAL_WITHOUT_VAT',$currencyHelper->format($data->cart->order_subtotal - $data->cart->order_subtotal_no_vat + $data->cart->order_shipping_price - $data->cart->order_shipping_price/1.21,$data->order_currency_id)).'</td></tr>';
Note: I had to translate the Tax Name (IVA) and put it as a label in TOTAL_WITHOUT_VAT, because the VAT and TAXES label, if used, the amount will not come out.
Regarding the Customer email, I just left it the way it is, maybe I will change it later.
I also had to change the
invoice.php file to show the items as I needed.
Invoice.php file:
Shipment cost WITHOUT TAX:echo $this->currencyHelper->format($this->order->order_shipping_price/1.21,$this->order->order_currency_id);
Total TAX (items + shipping):echo $this->currencyHelper->format($taxes+$this->order->order_shipping_price-$this->order->order_shipping_price/1.21,$this->order->order_currency_id);
Hope this helps everybody else having the same problem!