I finally got the second part of the mission to work, myself. All it took was to reset the APEngine.ini file to original settings, meaning
UseBackgroundLevelStreaming=true
OnlyStreamInTextures=false
OneFrameThreadLag=true
and then playing the game on the lowest resolution. I also did the flicking thing, where you allow the ID meter to fill just a bit at a time with the black guy in the suit, Van Graaf and that Corsa stripper woman, though I don't know if that helped.
Hope this helps someone.