When I make a sale, if I check the customer statement I get a line with the tax amount payable to customer, I also get the full invoice amount receibable (which is OK).

As a workaround I created a partner with the name of the tax authority and modify the line and change the customer name and put the tax authority there.

This works because a have that sales tax to pay.

I think the tax should not be automatically assigned to the customer.

What am i doing wrong?

Please help.