some of the items have to be restricted

Hi Guru's

While creating Quotation, the first line item should be finished material and from the second line item are Raw materials will be entered manually.

So customer requirement is that when creating a sales order with reference to Quotation,system has to restrict the raw materials.

Here BOM is not used b'cauz of the materials to be entered manually

Kindly let me know how to achieve this requirement or is there any USEREXIT to achieve this

Regards

Stephd