The Westpac Group pinpad supports any surcharges that are applied to the sale by the bank (e.g. a surcharge for using a specific card type).
Surcharges that are applied to the sale (due to payment by a specific card type) are sent back to Idealpos and are recorded against the Undistributed Link - Surcharges.
Therefore, it is important that you configure your Undistributed Links - Surcharges.
This is configured by going to: Setup > Global Options > Sales > Undistributed Links > Surcharges.
The Surcharges are linked to a dedicated Surcharge Stock Item. When any surcharges are applied, they will be recorded against the Stock Item that is linked under Undistributed Links > Surcharges.
For more information about this function, click here