OK, I got it to work. Inserting a MST from the BIAB VST3 into Reaper.
Given that a MST can actually be used in the VST I have to acknowledge that my issues up to this point have been user error. For all I know the instructions are in the Manual.
However, since the work flow I had to discover to get it done is so convoluted, combined with the fact that no one else seems to be having this issue, I am not going to share it. I simply had to work too hard to discover this and for all I know I am the only one who knows this workflow therefore I may now have a competitive advantage with my music.
But if you really want to know, PM me and I will share privately.