I solved my problem partially and now my invoice look like Product - Model - Price (ex) - Tax rate - Price (incl) - Total (ex) - Total (incl)

All i did was changed the admin/super_invoice.php like this:

original (at line 221):
Code:
<?php
    for ($i = 0, $n = sizeof($order->products); $i < $n; $i++) {
      echo '      <tr class="dataTableRow">' . "\n" .
           '        <td class="dataTableContent" valign="top" align="right">' . $order->products[$i]['qty'] . '&nbsp;x</td>' . "\n" .
           '        <td class="dataTableContent" valign="top">' . $order->products[$i]['name'];

      if (isset($order->products[$i]['attributes']) && (($k = sizeof($order->products[$i]['attributes'])) > 0)) {
        for ($j = 0; $j < $k; $j++) {
          echo '<br /><nobr><small>&nbsp;<i> - ' . $order->products[$i]['attributes'][$j]['option'] . ': ' . $order->products[$i]['attributes'][$j]['value'];
          if ($order->products[$i]['attributes'][$j]['price'] != '0') echo ' (' . $order->products[$i]['attributes'][$j]['prefix'] . $currencies->format($order->products[$i]['attributes'][$j]['price'] * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . ')';
          if ($order->products[$i]['attributes'][$j]['product_attribute_is_free'] == '1' and $order->products[$i]['product_is_free'] == '1') echo TEXT_INFO_ATTRIBUTE_FREE;
          echo '</i></small></nobr>';
        }
      }

      echo '        </td>' . "\n" .
           '        <td class="dataTableContent" valign="top">' . $order->products[$i]['model'] . '</td>' . "\n";
      echo '        <td class="dataTableContent" align="right" valign="top">';
      if ($display_tax) {
        echo zen_display_tax_value($order->products[$i]['tax']) . '%';
      }
      else {
        echo ENTRY_NO_TAX;
      }
      echo '</td>' . "\n" ;
    if ($display_tax) {
      echo '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format($order->products[$i]['final_price'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format(zen_add_tax($order->products[$i]['final_price'], $order->products[$i]['tax']), true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format($order->products[$i]['final_price'] * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format(zen_add_tax($order->products[$i]['final_price'], $order->products[$i]['tax']) * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n";
      echo '      </tr>' . "\n";
    }
    else {
      echo '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format($order->products[$i]['final_price'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format($order->products[$i]['final_price'] * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '      </tr>' . "\n";
    }
    }
?>
to this:
Code:
<?php
    for ($i = 0, $n = sizeof($order->products); $i < $n; $i++) {
      echo '      <tr class="dataTableRow">' . "\n" .
           '        <td class="dataTableContent" valign="top" align="right">' . $order->products[$i]['qty'] . '&nbsp;x</td>' . "\n" .
           '        <td class="dataTableContent" valign="top">' . $order->products[$i]['name'];

      if (isset($order->products[$i]['attributes']) && (($k = sizeof($order->products[$i]['attributes'])) > 0)) {
        for ($j = 0; $j < $k; $j++) {
          echo '<br /><nobr><small>&nbsp;<i> - ' . $order->products[$i]['attributes'][$j]['option'] . ': ' . $order->products[$i]['attributes'][$j]['value'];
          if ($order->products[$i]['attributes'][$j]['price'] != '0') echo ' (' . $order->products[$i]['attributes'][$j]['prefix'] . $currencies->format($order->products[$i]['attributes'][$j]['price'] * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . ')';
          if ($order->products[$i]['attributes'][$j]['product_attribute_is_free'] == '1' and $order->products[$i]['product_is_free'] == '1') echo TEXT_INFO_ATTRIBUTE_FREE;
          echo '</i></small></nobr>';
        }
      }

      echo '        </td>' . "\n" .
           '        <td class="dataTableContent" valign="top">' . $order->products[$i]['model'] . '</td>' . "\n";
      echo '        <td class="dataTableContent" align="right" valign="top"><b>' .
		              $currencies->format($order->products[$i]['final_price'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
			'		<td class="dataTableContent" align="right" valign="top">' . zen_display_tax_value($order->products[$i]['tax']) . '%</td>' . "\n" .  
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . 
		   $currencies->format(zen_add_tax($order->products[$i]['final_price'], $order->products[$i]['tax']), true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
		  ' <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format($order->products[$i]['final_price'] * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n" .
           '        <td class="dataTableContent" align="right" valign="top"><strong>' . $currencies->format(zen_add_tax($order->products[$i]['final_price'], $order->products[$i]['tax']) * $order->products[$i]['qty'], true, $order->info['currency'], $order->info['currency_value']) . '</strong></td>' . "\n";
      echo '      </tr>' . "\n";
    }
?>
NOTE: you will also need to change some lines above because i changed the order of elements.

Change to something like this:

around line 207 change:
Code:
<td class="dataTableHeadingContent" colspan="2"><?php echo TABLE_HEADING_PRODUCTS; ?></td>
        <td class="dataTableHeadingContent"><?php echo TABLE_HEADING_PRODUCTS_MODEL; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TAX; ?></td>
        <?php if ($display_tax) { ?>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_PRICE_EXCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_PRICE_INCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TOTAL_EXCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TOTAL_INCLUDING_TAX; ?></td>
        <?php }
        else { ?>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_PRICE_NO_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TOTAL_NO_TAX; ?></td>
        <?php } ?>
to this:
Code:
<td class="dataTableHeadingContent" colspan="2"><?php echo TABLE_HEADING_PRODUCTS; ?></td>
        <td class="dataTableHeadingContent"><?php echo TABLE_HEADING_PRODUCTS_MODEL; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_PRICE_EXCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_PRICE_INCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TOTAL_EXCLUDING_TAX; ?></td>
        <td class="dataTableHeadingContent" align="right"><?php echo TABLE_HEADING_TOTAL_INCLUDING_TAX; ?></td>

I hope this helps. Maybe i copied something wrong here - if so, contact me and i can email you complete file.

IMPORTANT: I use only one tax rate and don't have untaxable goods so this works for me. I don't know if it will work with different or no tax rates!

Anyway, it works for me...