Inquire>View Invoice

Greeting,

Have an query which when doing a PO enquiry, when I try to view the invoice of this PO under Inquire>View Invoice , it show that message that  " Function not available to this responsibility .Change responsibilities or contact your system administrator.

Have gone to  MENU option to view the  Purchase Order Summary , access, seem ok. What is missing in the setup ?

Would appreciate if any one can advice.

Thanks