From my (admittedly second-hand) understanding of the purpose for copying character data into the benchmark, I think you may be overestinating what it is achieving: it is just importing the character's appearance from the game with things like unlockable hairstyles that aren't naturally accessible in the benchmark character creator but must still be there in the program. Or even simpler, copying over the character to save you manually inputting each option and to ensure you don't make errors.

It isn't going to magically insert new gear models or do things that can't be done with the character, it's just instructions of which normal settings have previously been applied.

If a thing could be officially done within the game, there would be no point to placing it in an external program.