Rapid acceleration with model references for parameter swept

What is the proper way to perform efficently a batch of simulations (i.e., either a parameter swept or a Monte-Carlo analysis) under the following circumstance:

• the model to be simulated is complex, and it takes a while to build it (in accelerator/rapid mode)
• the model to be simulated is referencing other models (via model referencing)
• some parameters that need to be changed are field of a structure (e.g. gain=struct('a',1,'b',2) and I need to change gain.a)

In my opinion, the best would be building the model once, and change the parameters of interest between a simulation and the following. I tryed the approach described here defining the variables to be chanded as Simulink.Parameter and then using the command

rtp = Simulink.BlockDiagram.buildRapidAcceleratorTarget(mdl);

but unfortunately I wasn't able to transform stuctures into valid Simulink.Parameters