Create generic data extractor in BW system (transaction RSO2). It should be transaction data datasource.
It has to be based on MARM table. It contains information on how to convert from alternate unit of measure to base unit of measure. There are only 4 fields which are needed to accomplish materuial unit conversion in BW system (MARM-MATNR, MARM-MEINH, MARM-UMREZ, MARM-UMREN ). During the datasource definition all the other fields have to hidden. There is no need of generic delta definition, every time the loads will be full.
MARM table structure:
After the datasource is saved in ERP system it only needs to replicated in BW system.