inventory issue on calculating total stock

Hi Experts,

I have to implement inventory in my system and i need a help regarding total stock calculation via non cumulative key figures.

1) We have a field called MENGE (Quantity) in 2lis_03_bf, how do i derive issued stock and received stock from there. Is there any direct field in BF datasource? The reason i need this is i have to add them under Total stock object as non cumulative key figure to get total stock.

Regards,

Karthik.