You say in the original post "so I used the inner shifter to release all the tension on the cable".
If you did this after you threaded cable -- i.e. the shifter was not set this way when you threaded the cable -- then the cable could be threaded incorrectly. The shifter needs to be in neutral for cable to thread through and set properly. When cable is at maximum slack, you should be able to see the cable end inside the shifter seated in a cylindrical notch. Another way to test is visually. Compress the brake a bit as you shift and you should see the cable end within this cylinder begin to move towards you within the shifter.
Thanks. What is meant by "neutral" ? Do I start to thread with all of the slack out? All of the slack in? Or somewhere inbetween?