Configuration in Receivable R12 to pay Unrelated Party Invoice

Hi

In customer screen I have define the relationship between two parties. The current configuration do not allow to pay for invoices on behalf of unrelated parties.

I need to alter the configuration to be able to achieve this. I have already check the check box on Receivable setup option screen under Trans and Customers tab.

But this configuration does not allow me to archive this particular scenario. Is there any additional configuration that need to be done.

Any respond we be much appreciated.