How to apply three taxes at same time on same invoice

How to apply three taxes at same time on same invoice


Hallo: in Italy we have another kind of tax called "rivalsa" it is applyed to the professionists.
an example

service to be invoiced                             $ 100.00
rivalsa 4%                                               $     4.00
VAT 20%                                                 $   20.80
Ritenuta d'acconto -20%                         $ -20.80
total                                                        $ 104.00

How can I do that?
Thank's in advance
Massimiliano Scaletti