To add a new custom tax rate please go to 'Settings > Misc. > Exchange Rate'
Then click the 'New Exchange Rate' button.
Select the currency exchange you wish to make from the 'Exchange' drop down box and click the 'Add Exchange Rate' button.
You will see the 'Edit Exchange Rate' page. This will show you the current exchange rate between your selected currencies and the last date this rate was checked. Enter a 'Overhead Percentage' into the corresponding field and click the 'Save' button.
Your new exchange rate has now been added.
The automatic exchange rates are checked daily around 4pm and are taken from the following source: https://openexchangerates.org/
Setting a Manual Exchange Rate
It is also possible in storefeeder to set a manual exchange rate, you can enter this if you purchase currency at particular rate for a period of time to help make the currency conversions in storefeeder more accurate.
To set a manual rate you just need to tick the "Override exchange rate" tick box as shown below:
When you tick this box a new field called "Manual Rate" will appear. To set your own rate you simpley need to type the rate you are using into this field to a few decimal places for precision and then hit the save button to save rates you entered.
Now when we import orders we will set the conversion rate using the rate you have added. We set the rate against orders on import so the conversion for old orders will not change when you change this field.