MATLAB: How to set Stateflow Model Explorer properties in M-script

model explorerstateflow

In Simulink, Block-properties / handles can be viewed and set using the 'get_param' and 'set_param' commands, respectively. I would please like to know how to do so for Stateflow data (Model Explorer) using matlab script (i.e. in m-file).
>> Example: I have a Model "TestModel.mdl" which has a SF_chart in deeper layers: "TestModel/SubSystem_1/MyChart" for which I need to Add Data;
Name: PRES_C
Scope: Parameter
Type: Double