public function tagPISST($nItem = '', $vBC = '', $pPIS = '', $qBCProd = '', $vAliqProd = '', $vPIS = '')
{
$pisst = $this->dom->createElement('PISST');
$this->dom->addChild($pisst, 'vBC', $vBC, true, "[item {$nItem}] Valor da Base de Cálculo do PIS");
$this->dom->addChild($pisst, 'pPIS', $pPIS, true, "[item {$nItem}] Alíquota do PIS (em percentual)");
$this->dom->addChild($pisst, 'qBCProd', $qBCProd, false, "[item {$nItem}] Quantidade Vendida");
$this->dom->addChild($pisst, 'vAliqProd', $vAliqProd, false, "[item {$nItem}] Alíquota do PIS (em reais)");
$this->dom->addChild($pisst, 'vPIS', $vPIS, true, "[item {$nItem}] Valor do PIS");
$this->aPISST[$nItem] = $pisst;
return $pisst;
}