i have to post this vendor invoice :
The 0.90 is a tax withholding (and it is different from VAT), but is seems that this functionnality is not completely done in Compiere.
So i used a charge to make it possible.
So with this solution, i got an amount for VAT and IRPF. I will pay later this amount using the bank statement.
I'd like to know if there is another way to do it.
Sorry W, up until release 3.0.2, the witholding seems not work yet. Maybe in 3.1 it will work.