BPA Invoice - Contact Phone

Using Bill Presentment Architecture, we developed a custom BPA Invoice that we created from the seeded BPA Invoice.  It appears that the field called 'Contact Phone' only pulls in the 7 digit phone number associated with the customer contact, but we would like to include the area code as well.  I've looked at trying to update the 'Invoice Header View' under the 'Oracle Receivables' Data Source under Configuration, but I don't see how to modify this to add in the area code.  Has anyone done this before, or is it even possible?

Thanks in advance.