Paypal in Engish and spanish

Hello all.
I have my Zen store in both english and spanish. I can edit all the file for both languages very easy in the Define Pages Editor for: xxx.

My main question is how do I make the zen cart take me to the spanish paypal when the user chooses spanish and so on. I have tried finding the location to change it but the defalt location is in "includes/modules/payment/" when i click on the spanish link in the admin it looks for the payment in the same location.

I do understand that i need to input https://www.paypal.com/**es**/cgi-bin/webscr for spanish and https://www.paypal.com/cgi-bin/webscr for english. nothing seems to work for me.

can anyone help? i have tried to look for a similar question but i guess i have missed it somewhere.