For my male albino boa that decided to be picky and only want live I had quite a time working with him to figure out what I'd have to do to get him to take f/t.
Finally he started excepting them if I would run a pan full of super hot water from the sink, toss the frozen mouse/rat in the water itself to soak into the skin and hair, once it's thawed after an hour or so take it out dump the water and run fresh super hot water in the pan again, put the rat in it, and then just pick it up with the tongs by the tail or back legs and shake most of the water off, and then offer it to him.
Somehow it seems like the fresh hot water really put that scent out there because he would already be coming out looking for food before I even walked into the room. It just took me just short of a year to actually get to this method and to get him to decide it was ok for him.
I tried everything from scenting to braining to assisted feeding(he hated this the most and never ate once with this) and finally, heating with an outside heat source that left the mouse/rat dry but warm/hot, such as with a hairdryer, heat lamp or heating pad. But he would still only accept live up until I tried the soaking in hot water idea and since then he's had no problem staying on schedule and taking his f/t meals.