The developer is not being responsive in our requests to create a fully silent package.
My misunderstanding; I thought this developer was in-house.
In this type of case, will an .mst file potentially be needed?
Well, that depends. Do you need to customize any of the options in the default installation?
I clicked on your link above, but it did not answer the question below:
If an .mst file is needed in this case, could you provide some examples of a manually written .mst file that might work that I can try out?
Or will I have to go back to the non-responsive developer?
Really. Hmmm.
Try this: A Customization Transform Example (Windows)
But, generally speaking, the specific options that could go into an MST file are something that would be defined (and presumably documented) by the software developer.