In order to have a spike relay shift in both directions, you are going to have to do several things. Hardware, 1, create a cable, see link below, you are going to use two cortex digital outputs to energize two solenoids. The middle pin(red) is not connected on the cortex, nothing is soldered to either red pin on cortex side. The cable is going to be plugged into two digital outputs on cortex. Plug the other single side into the spike. The spike is able to output voltage through both terminals, see link below, and can use a common ground from inside your controller box. Software, after you start a new project, click on project, and then controller configuration, you will see the digital outputs, change the ones you wish to use(at least two) to outputs by clicking on the icon and having arrow point outward. They are now outputs. In your program, create a joystick to digital output, and assign one button to fire your first digital out, and a second button to fire a second digital output. We have this set up on our robot following and it works, good luck.
Official Answer: Mike Martus
The information from Bernie - is great and he had it working last year.