Default [Q] Changing the camera-app WhatsApp uses?

Hi,

i am currently trying to get WhatsApp to use the camera App of my choice (Focal) instead of the stock one.
I already tried moving Focal to the system Apps, as that was suggested in other threads.
Also i deactivated the gallery and camera app to force WhatsApp to use the remaining camera App on the device, yet to no avail.

WhatsApp now simply declares, that there is no application that could be used to take a photo.

I am currently using the CM11 Nightly-build on my Xperia Z.

If anyone could help me with this i would be really gratefull.