HERO3+ cameras with a Battery BacPac or LCD Touch BacPac attached are not currently supported with the Waterproof Housing that comes with HERO3+ cameras. If you try to use the BacPac with the HERO3+ Waterproof Housing, you will notice that the BacPac Backdoor does not fit onto the HERO3+ Waterproof Housing.
To use a HERO3+ camera with the Battery BacPac or LCD Touch BacPac attached, you will need to use the HERO3/BacPac Compatible Housing, which can accommodate the BacPac Backdoor. So if you own a HERO3 camera, the best solution is to just use the HERO3 housing with your HERO3+ camera and BacPac. If you have a HERO3+ camera and do not already have the HERO3 housing, please contact Support for a solution.