* Load Specific Document Details
* @return error message or null
*/
protected String loadDocumentDetails ()
{
MInvoice invoice = (MInvoice)getPO();
setDateDoc(invoice.getDateInvoiced());
setIsTaxIncluded(invoice.isTaxIncluded());
// Amounts
setAmount(Doc.AMTTYPE_Gross, invoice.getGrandTotal());
setAmount(Doc.AMTTYPE_Net, invoice.getTotalLines());
setAmount(Doc.AMTTYPE_Charge, invoice.getChargeAmt());
// Contained Objects
m_taxes = loadTaxes();
p_lines = loadLines(invoice);
log.fine("Lines=" + p_lines.length + ", Taxes=" + m_taxes.length);