Something like this should work.
function create_Buses()
% Bus object
clear elems;
elems(1) = Simulink.BusElement;
elems(1).Name = 'BusSig_1';
elems(1).Dimensions = 1;
elems(1).DimensionsMode = 'Fixed';
elems(1).DataType = 'uint32';
elems(1).SampleTime = -1;
elems(1).Complexity = 'real';
elems(1).Min = [];
elems(1).Max = [];
elems(1).DocUnits = '';
elems(1).Description = '';
elems(2) = Simulink.BusElement;
elems(2).Name = 'BusSig_2';
elems(2).Dimensions = 1;
elems(2).DimensionsMode = 'Fixed';
elems(2).DataType = 'uint32';
elems(2).SampleTime = -1;
elems(2).Complexity = 'real';
elems(2).Min = [];
elems(2).Max = [];
elems(2).DocUnits = '';
elems(2).Description = '';
elems(3) = Simulink.BusElement;
elems(3).Name = 'BusSig_3';
elems(3).Dimensions = 1;
elems(3).DimensionsMode = 'Fixed';
elems(3).DataType = 'uint8';
elems(3).SampleTime = -1;
elems(3).Complexity = 'real';
elems(3).Min = [];
elems(3).Max = [];
elems(3).DocUnits = '';
elems(3).Description = '';
BusData = Simulink.Bus;
BusData.HeaderFile = '';
BusData.Description = '';
BusData.DataScope = 'Auto';
BusData.Alignment = -1;
BusData.Elements = elems;
clear elems;
assignin('base','BusData', BusData);