Default [Q] Disabling S Voice


I'm new on this forum and I have a question for you all. I am building an app that will activate by pressing the headphone button while screen is off, however I'm having trouble because S-Voice activates instead of my app. I can get it working while the screen is on, by disabling the S-Voice shortcut. The thing is I still want the S-Voice service to run in the background and the users being able to access it, but only by going into the app itself, and not via some kind of shortcut. Root is not an option.

Any ideas on how to tackle this?

Thanks in advance,