Total sum of the lines of an invoice

Hi everybody.

My name is Nancy and I wanted to ask you the following question:

Does anybody know if there is some way to configure or set up the AR module (eBusiness Suite R11.5.10.2), for not allow to having a negative value as the result of the sum of all the lines of an invoice.

For Example an invoice wich has the following values:

Class: Invoice

Its total value must be positive, because it is an invoice.

Total sum of the lines of the invoice = -1

Total sum of the taxes of the invoice = 3.93

Total of the invoice                  = 2.93

I have created this invoice in AR module.