IS-Retail: Update article Purchasing Info Record

Hello,

are there BAPIs or Function Modules in IS-Retail to updaten the Purchase Info Records of an article?

I am trying to update the fields EINA-IDNLF (Vendor material number) and EINA-LTSNR (Vendor Sub-Range).

It seams that the standard IS-Retail article üpdate BAPI: BAPI_MATERIAL_MAINTAINDATA_RT does not support the update of the Info Record of an article/vendor

Thanks,

Manuel