Thanks Xavier.
Whith your suggestions I was able to do the following:
<?php
$currencyClass = hikashop_get('class.currency');
$converted_price = $currencyClass->convertUniquePrice($this->order->order_full_price,$this->order->order_currency_id,1);
echo 'Total: '.$currencyClass->format($converted_price).'<br>';
echo 'Rate: '.$this->order->order_full_price/$converted_price;
?>
Sale in SEK, Primary currency=EUR
This gives the output:
Total: 40,66 €
Rate: 8.4557
So far so good. BUT IT IS WRONG! Stay with me and I will explain. The output is dynamic. It shows the rate on todays rates. So it only will be valid on the day for the sale. When looking at an order/invoice e g one week later it shows a different rate. WRONG!
Solution:
I have to make a database entry and put the rate for the sale and store it the same day the sale takes place. Then when looking/printing at the invoice the rate is fetched from database.
Could you please give me a hint on how to do this.
/Mathias