The system should zero out the wholesale tax amount, but that will only work if Mals is set up to use the tax in the buy buttons - which means that you'd have to set a tax amount for each of the items in the Tax % field.
You can add tax amounts to an item. To do this, you first have to turn on the Tax settings:
1. Access the /storeadmin/ area.
2. Select Catalog Setup.
3. Set Tax/Costs to 'Yes'.
4. Now go in to the 'Products' arae.
5. Select the individual product that is to be taxed.
6. Edit it and enter...