Leonildo,
For a purchased MTS part, you normally do not send a BOM to the vendor with the purchase order as part of the planning process. The specifications for manufacturing are handled outside the planning system; your specifications department sends appropriate technical documents to the vendor which give him manufacturing details of the material that you wish to purchase from him. These documents may accompany the purchase order, or they may be sent in anticipation of the purchase order, and the vendor is instructed to keep them on file.
You did not mention whether you also intend to supply component materials to the vendor, nor whether you wish to plan these components on your local system. For this, you normally use a subcontracting scenario.
http://help.sap.com/erp2005_ehp_04/helpdata/EN/4d/2b900743ad11d189410000e829fbbd/frameset.htm
Best Regards,
DB49
