When assigning keyboard shortcuts in APub there is an option “Apply to all”, which means that the new shortcut will work for any Persona.
You can choose Photo Persona and assign the shortcut for, say, “Layer > New Fill Layer”.
It will work amazingly OK in Publisher Persona, though there is no such menu command there (Publisher does not have Fill Layer in it’s menu).
But it only works until the program restart. Sadly enough.