WHMCS credit added before Tax add

[KNK]

WHMCS, when I add credit calculates final price by doing the following;

Server price + Tax LESS credit of the account.

This is BAD for EUROPEAN Tax.

My accountant said that, you need to do like;

Server price LESS credit + Tax.

How can I change in WHMCS to add CREDIT before ADDING TAX?

[Remitur]

Sadly, you can't. It's years we have asked for it, but WHMCS decided that adding GBs of useless commercial add on was more important.

There's a module (BX2 by Katamaze) that does this, but it's far from being perfect (I'm using it, but there're no alternatives)