After e few try I've come up this this partial solution:
in ...includes/modules/Your_template/attributes.php I've made this modifications (line 181...):
PHP Code:
// normal price
                        
if ($new_attributes_price == 0) {
                          
$products_options_display_price'';
                        } else {
                          if (
$_SESSION['customer_whole'] && $_SESSION['customer_whole'] != '0' ) {
                             
$products_options_display_priceATTRIBUTES_PRICE_DELIMITER_PREFIX $products_options->fields['price_prefix'] .
                             
$currencies->display_price([COLOR="#FF0000"][B]$new_attributes_price_w[/B][/COLOR], zen_get_tax_rate($product_info->fields['products_tax_class_id'])) . ATTRIBUTES_PRICE_DELIMITER_SUFFIX;
                          } else {
                            
$products_options_display_priceATTRIBUTES_PRICE_DELIMITER_PREFIX $products_options->fields['price_prefix'] .
                            
$currencies->display_price($new_attributes_pricezen_get_tax_rate($product_info->fields['products_tax_class_id'])) . ATTRIBUTES_PRICE_DELIMITER_SUFFIX;
                          }
                        }
                      }
                    } 
The $new_attributes_price_w should be the key to its working. Actually if the customer is not logged or doesn't have Wholesale status it will show the correct (+€something) but if it has wholesale staus and log it anly show a (+€0.00). If some one can help with it i'll appreciate