Hi Kian,
thanks for taking the time to answer. Unfortunately we can't do that declaration bit, you know Germans, everything has to be following the rules very strictly ;-)
Do you mean the invoicepdf.tpl? I would love to do that, but as I found out here http://forum.whmcs.com/showthread.php?22916-V4-Invoice-Template-Calculations-Stopped-Working&highlight=calculate+invoice I can't simply caclulate with the value, since $invoiceitems[amount] delivers a string. Any ideas around that?
The other way around, i.e. using prices excluding VAT and then calculate the gross price for output on the web, would be good too, but I haven't yet found how to do that either :-(