I think you have it. I do remember carefully cutting braid also. That is likely your power plug. The fiber loop you mention, probably a rectangular plastic coupler that aligns two separate cables so the light circuit is completed. You would unclip both cables and insert into the CDC. You will see more of these in trunk under driver side hinge for the factory in adding sat radio and HD tuners...
2007 650i Stratus Gray Black/Beige, 6MT trans, 7MP/ZSP Sport Pkg, ZCW Cold Weather Pkg, 609 Navigation, 610 HUD, 611 Night Vision, 322 Comfort Access, 677 Logic 7, 653 HD Radio, 655 Satellite Radio.