Tax classification in intercompany transactions

Hi experts,

I'm having problems with the Tax Classification in my intercompany invoices.

Let me explain my problem. I'm doing all the process for intercompany invoices. I have my AR transaction in Portugal and then I run the different concurrent processes to have may AP invoice in Spain. My surprise comes when I see that the tax classification in the line is the one from Portugal. Does anybody knows what I have to do in order to have the correct tax classification?

I have read few notes but I don't understand quite well what I need to do

Thanks for your help.