Hi Ton
There is no formattedPriceWithTax, but you can try to do something like taking the total amount with tax and divide by the quantity and multiply by your exchange rate. Then you want to round the number to 2 decimal places and prepend the "EUR".
{xsl:value-of select="concat('EUR ', replace(format-number(totalAmountWithTax div quantity * /in/salesOrder/exchangeRate, '##0.00'), '.', ','))" /}