TMVA binning

Hello, I’m trying to modify the binning of the TMVA output:

    TMVA::Factory* factory = new TMVA::Factory("calibration_MVA",
                                               &output_file);
    (TMVA::gConfig().GetVariablePlotting()).fNbinsMVAoutput = 200;
    (TMVA::gConfig().GetVariablePlotting()).fNbins1D = 500;
    (TMVA::gConfig().GetVariablePlotting()).fNbins2D = 500;

it seems not to work with ROOT 5.30/04. The binning is always 50x50