To do this, I need to understand what PDBSTR.EXE does. This is what I have to go on:
Once the code has looked at all the source files in the PDB file, it's time to call PDBSTR.EXE to write the index stream, called SRCSRV, to the PDB file. When debugging, the debugger looks for this stream. If it is found, the debugger knows there's a source server involved and calls into SRCSRV.DLL to execute the version control system to ensure the right file is accessed.
I've been studying the pdb files pre and post indexing to gain insight into what happens when I use the Debugging for Windows srcsrv tools. Circling the symbolstore.py code getting ready to make changes to see what I can do.
Any minute now the big picture will come into focus...back to my pdb files.