http://svendus.se/blog/?page_id=1889
Before you go to Equirectangular Projection mode you have to go to layers and check the back ground.
Working in the Equirectangular Projection mode, and before saving you must leave the Equirectangular Projection mode and merge layers if you want further instructions click the ? sign in the top right corner of the application 
To day the 360 photographer that before was behind the camera have now become in the Center, but Affinity Photo can change this
Regards Svendus