You should use ApplyMap in the where statement instead of fields:
InitialData:LOAD * INLINE [ CAMPOb, CAMPOa A, bA A, LL AA, cc GG, k GG, z A, VV];Map:MAPPING LOAD CAMPOa AS CMP01, CAMPOb AS CMP02RESIDENT InitialData;Result:LOAD CAMPOa AS STEFFRESIDENT InitialDataWHERE ApplyMap('Map',CAMPOb) = 'A';