You can do this by creating a virtual outlet with Apex. Then in your control program, reference this outlet at the end of your code. For example, name your virtual outlet VR. At the end of your control statement type if outlet VR = OFF then off. Normally, control VR is set on for normal programing. But when you manually set VR to off, it will turn the pump off without the backup battery coming on.
There is a little trick to create the virtual outlet in the first place in the modules page, you may need to research this in the apex section.