Sales Organization Unit always Mandatory in Business Transaction

Dear experts,

We are using SAP CRM 7 with web UI. I want to make Sales Organization to be not mandatory in Business Transaction (Service Request). I have Maintained Organizational Data Profile in SPRO and set Sales Organization became not mandatory. But when I made a service request, I always found error message "Enter Sales Organization Unit (Sales). I also have blank the Organizational Model Determination Rule and Responsibilities Determination Rule, but the error message still appeared.

Please kindly advise me what to do.

Thanks & Regards,

Shafeeg