Terms of Payments

Dear all,

I need for some customers in France/Italy to set the Terms of Payment in a particular way. Basically should be:

From date of invoice, adds 45 days, and then go to end of the months. So to make an example

Date of invoice: 11 August

Plus 45 days: 25 September

End of months: 30 September

So the due date of the invoice is September 30th.

I can't find a way to create this in SAP. Any suggestion?

Thank you