From the Model menu, select Get Measures from BIM file. This opens a .dax file
Edit measures in the .dax file.
To save your new or modified measures to the .bim file (WARNING: measures missing in DAX file will be removed!): --> Close the .bim file. --> Click the DAX file to activate. --> Select DAX->Save Measures to BIM file. --> Reload the BIM file. New measures appear in the far left corner of the measure grid.
To get measures from the BIM file to the DAX file: --> Save the .bim file. --> Select DAX->Get Measures from BIM file. The contents of the DAX file are overwritten with the measures from the BIM file.