Process
1.Create the semi finished goods material code. Tcode MM01
2.Maintain the BOM for the material. Tcode CS01
3.Create PO with item category as "L" . Tcode ME21N
4.Issue raw material to vendor with movement type 541 Tcode MB1B
5.Receive the material against the PO with movement type 101. Tcode MIGO
6.MIRO to account for vendor's invoice for the service charge& material used by him. Tcode MIRO
Refer Old thread.
Regards
MS