Tax issue on Receivable Invoice

Our client has a requirement to enable both Oracle Tax and Vertex for Receivable Transactions. So, we have implemented the Vertex for US based customers and it is working properly however, Vertex is not calculating the tax for foreign customers( Example, Bill-To & Ship-To is Singapore) that's because the Vertex is implemented only for US country.

Can we enable Fusion Tax also for Receivables to work only for foreign customers?