The Shimano 7 gear hub with a roller brake is a very common hub for city bikes in the Netherlands. Sooner or later one needs to be able to remove the rear wheel with this hub, e.g. to fix or replace a flat tire. Releasing brake cable for the Shimano roller brake is easy, just press the brake lever forward as, a like the good old Sachs drum brakes. A small trick to release the gear change cable for the Shimano 7 gear hub. See the small hole pointing backwards in the plastic ring closest to the gear/chain? Insert a 2mm Allen key there and use that to lever the ring forward, and use needle-nose pliers to release the cable end. Easy :)