OVM: Unable to change objects default configuration

Hi all,

I am just building a verification environment pretty similar to one in the XBUS examble.

I've got problems override a default values of user-configurable variables using configuration interface (set_config_int method).

My top level object cmux_tb instatiates enviroment switch_env (an OVC) and configures it:

class cmux_tb extends ovm_env;

  `ovm_component_utils(cmux_tb)
 
  // the Switch environment
  switch_env cmux_env;

  virtual function void build();

    super.build();
   
    set_config_int("cmux_env", "num_inputs", 3);
    set_config_int("cmux_env", "num_outputs", 1);
    set_config_int("cmux_env", "bus_width", 1);
    set_config_int("cmux_env", "ctrl_width", 2);
 
    cmux_env = switch_env::type_id::create("cmux_env", this);

  endfunction : build

...

endclass : cmux_tb

The switch_env has defined (and registerred in a Factory) the above mentioned varibles:

class switch_env extends ovm_env;

  // environment properties
  protected int unsigned  num_inputs = 0;
  protected int unsigned  num_outputs = 0;
  protected int unsigned  bus_width = 0;
  protected int unsigned  ctrl_width = 0;

 `ovm_component_utils_begin(switch_env)
    `ovm_field_int(num_inputs, OVM_ALL_ON)
    `ovm_field_int(num_outputs, OVM_ALL_ON)
    `ovm_field_int(bus_width, OVM_ALL_ON)
    `ovm_field_int(ctrl_width, OVM_ALL_ON)
  `ovm_component_utils_end

... 

endclass : switch_env 

When I print the topology after elaboration, I realize, that those varibles remains set to 0. When I use the same approach to object instatiated inside switch_env, the configuration works fine.

Can somebody tell me what I am doing wrong?

Thanks for help,

Jan