Utilizing a structure as a tunable parameter with RSIM

I'm attempting to setup a simulation using the RSIM target. I have a number of inputs coming into the model as tunable parameters. I would like these values to be contained inside a structure. I've setup this structure inside a Simulink.Parameter in a data dictionary, with the storage class set to "SimulinkGlobal" and also applied a bus object data type to the Simulink.Parameter. I've also tried setting the storage class to "ExportedGlobal.

After setting all this up, I see the variable in the returned structure from rsimgetrtp, however when modifying the data inside this structure and saving as a .mat file to feed to the .exe generated from rsim the parameters appear to not be modified.