create material using bapi_material_savedata

Hi.

I'm having prob with creation of material using bapi_material_savedata. When creating new material we use internal numbering so I use first bapi_material_getintnumber'. the number from that bapi is what i used in bapi_material_savedata. However, I getting an error that says 'matnr <from bapi>does not exists', why is this so? do i need to put the commit after the bapi_material_getintnumber and before calling the bapi_material_savedata?

Please help.

thnx.