Just another thought:
If you wait until they actuially offer it to you it will at that point become a confrontation where you'll either cause a scene or accept it against your will. It's much better to nip it in the bud, as I suggested.
Further, there's an issue of personal integrity. When they ask you the usual question: "do you know of any reason why you shouldn't be appointed a Ministerial Servant?" your mind is immediately going to go to all the things you no longer believe. I suspect you can't answer that question honestly in the way they'd want.