Block posting for Obsolete Materials in COPA

Hey All

We ahve a ascenario in which we post some expenses to the materials via FI transactions FB50. Nothing hits the stock accounts in these transactions. Only thing is while posting we assign the Materials to the PA segment so that we can run reports in COPA for the materials

Now some materials have been discontinued and the material plant status have been set to NOT to perform any transaction related to supply chain. BUT when posting through above FB50 trasnaction the system does stop it from posting and derivation for the obsolete material. I have even tried setting the deletion flag in MM06 for the material. Is there any solution to this so that we can stop material from posting

Thanks

Ankur