Struct as Tunable Parameter in Simulink Real-Time C API

Background

I am using both Simulink Real-Time Explorer as well as the Simulink Real-Time C API. Eventually, I want to fully switch to the C API, however, for now I am using Eplorer to test and debug my models.

I was expecting both to behave (about) the same. A mismatch arises, though, when I am using a struct as tunable parameter. In Simulink Real-Time, the struct is visible and tunable as expected. However, from the C API, only boolean/double data types are visible, not the structs.

More digging into the problem shows below result. Even from within MATLAB, 'NumParameters' is '3' (the amount of parameters not counting the structs), but the parameters shown does include the structs. When requesting the parameter ID for a struct parameter, no result is returned.

Question

This leads me to think there is a special way to retrieve the structs. Is it possible to access struct parameters from the Simulink Real-Time C API? Or otherwise access struct parameters programatically (e.g. the MATLAB command line)?

Example code

Showing parameter names from the MATLAB command line. 'NumParameters' == 3, but more are shown.

>> tg = slrt;
>> tg.ShowParameters = 'on';
>> tg
Target: VirtualBox
   ...
   NumParameters        = 3
   ShowParameters       = on
   Parameters           = VALUE             TYPE      SIZE        PARAMETER NAME                BLOCK NAME                    
                         [...]              STRUCT    Scalar      param1                                              
                         [...]              STRUCT    Scalar      param2                                              
                         [...]              STRUCT    Scalar      param3                                            
                         298.15             DOUBLE    Scalar      param4                                             
                         [...]              STRUCT    Scalar      parma5                                         
                         [...]              STRUCT    Scalar      param6                                         
                         1                  BOOLEAN   Scalar      param7                              
                         0                  BOOLEAN   Scalar      param8                                  
             

Retrieving the parameter ID of a struct parameter is not possible.

>> tg.getparamid('', 'param3')
ans =
     []