[GNC] Help adding withholding tax and VAT in seperate fileds of the invoice.

[Nikos Parafestas]

Beacuse of the taxation sytem in my country I need to add withholding
tax and VAT in seperate fields in the invoice. This applies to every
tansaction with a net price of 300 euro or more.
For example if the Net Price is 1000 euro the invoice should include
the following:
---
1. Net Price = 1000 euro
2. VAT = 240 euro
3. Total Price 1240 euro
4. Withholding Tax (which is 20% of the Net Price. This amount the
client pays directly to the goverment not to me) = 200 euro
5. Payable (Total - Witholding Tax) = 1040 euro 
----

1-3  : I have managed to add them correctly
4 & 5: I don't have a clue how to add them.

I hope I made it clear.

ps. If you want to help I would like to ask you to provide your answers
in a way that a novice user like me can understand.