How to get Gross price to show and not nett in store and admin?

[hauruapai]

ok, fyi here is how to get the gross price to show in your shop:

admin/includes/modules/product/preview_info.php

around line 56, change

<td class="pageHeading" align="right"><?php echo $currencies->format($pInfo->products_price) . ($pInfo->products_virtual == 1 ? '<span class="errorText">' . '<br />' . TEXT_VIRTUAL_PREVIEW . '</span>' : '') . ($pInfo->product_is_always_free_shipping == 1 ? '<span class="errorText">' . '<br />' . TEXT_FREE_SHIPPING_PREVIEW . '</span>' : '') . ($pInfo->products_priced_by_attribute == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_PRICED_BY_ATTRIBUTES_PREVIEW . '</span>' : '') . ($pInfo->product_is_free == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_IS_FREE_PREVIEW . '</span>' : '') . ($pInfo->product_is_call == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_IS_CALL_PREVIEW . '</span>' : '') . ($pInfo->products_qty_box_status == 0 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_QTY_BOX_STATUS_PREVIEW . '</span>' : '') . ($pInfo->products_priced_by_attribute == 1 ? '<br />' . zen_get_products_display_price($_GET['pID']) : ''); ?></td>

to

<td class="pageHeading" align="right"><?php echo $currencies->format($pInfo->products_price_gross) . ($pInfo->products_virtual == 1 ? '<span class="errorText">' . '<br />' . TEXT_VIRTUAL_PREVIEW . '</span>' : '') . ($pInfo->product_is_always_free_shipping == 1 ? '<span class="errorText">' . '<br />' . TEXT_FREE_SHIPPING_PREVIEW . '</span>' : '') . ($pInfo->products_priced_by_attribute == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_PRICED_BY_ATTRIBUTES_PREVIEW . '</span>' : '') . ($pInfo->product_is_free == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_IS_FREE_PREVIEW . '</span>' : '') . ($pInfo->product_is_call == 1 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_IS_CALL_PREVIEW . '</span>' : '') . ($pInfo->products_qty_box_status == 0 ? '<span class="errorText">' . '<br />' . TEXT_PRODUCTS_QTY_BOX_STATUS_PREVIEW . '</span>' : '') . ($pInfo->products_priced_by_attribute == 1 ? '<br />' . zen_get_products_display_price($_GET['pID']) : ''); ?></td>

(the products_price to products_price_gross)

admin/includes/modules/update_product.php

around line 24 / 25 find

    $tmp_value = zen_db_prepare_input($_POST['products_price']);
  $products_price = (!zen_not_null($tmp_value) || $tmp_value=='' || $tmp_value == 0) ? 0 : $tmp_value; 

replace with

//    $tmp_value = zen_db_prepare_input($_POST['products_price']);
 //   $products_price = (!zen_not_null($tmp_value) || $tmp_value=='' || $tmp_value == 0) ? 0 : $tmp_value;
        
        $tmp_value = zen_db_prepare_input($_POST['products_price_gross']);
    $products_price_gross = (!zen_not_null($tmp_value) || $tmp_value=='' || $tmp_value == 0) ? 0 : $tmp_value; 

find around line 44

'products_price' => $products_price, 

and replace with

 //  'products_price' => $products_price,
                                                        'products_price' => $products_price_gross, 

BUT, this does NOT change the price in the cart when the customer is outside the "zone" and therefore should not be paying the GST.

So now, How can I get:
1. nett price to show in cart when the customer is outside the "zone"
2. gross price to show in cart when the customer is inside the zone

Thank you for your time