//http://help.sap.com/saphelp_mdg80/helpdata/en/77/29ad50e6542f3ce10000000a44538d/frameset.htm
http://scn.sap.com/docs/DOC-42415
Hi Steve - sorry for the delay in responding to your question. We have lots of folks on holiday recently.
You might start with the attached links and let us know if you have more specific questions regarding use of MDG for spare parts.
Thank you and best regards,
Bob Bowser
Chemical Industry Leader, ENR Hub Services