Scirocco Register

You can pull the spring back by hand, then grip the cable with some long nose pliers. I do this as the first step of reassembly. If the cables have got old rusty springs on you can often do it without the pliers

put the whole back plate in a vice on bench ..easy to clean up and rebuild everything like new

You have a vice?! On a bench?!

You're obviously spoiled, some of us have to do it on the car, by the roadside, in the rain, on a severe gradient! :)

Seriously, I once replaced all the brake pipes on my long wheelbase Land Rover under exactly those circumstances, not fun, I look back now and wonder how hell I did it and lived to tell the tale without being confined to the loony bin.