Generating a Sale Order for a Service Item

Hi,

Requirement:

This is a company where they deliver project and support services, which include service items such as CRP Service, UAT Service & Go live.

When considering a milestone like a CRP Service, the customer make payment for its phase wise. So the company should have the possibility to Create Sales orders and invoice them line wise.

Error 

Once you booked the sales order (Service item), the status straight away changed to Awaiting Shipping instead of Supply Eligible. Simply this doesn't allow us to generate a PR and PO and run the process further.

Thanks in advance,

Sakith