I wonder sometimes if snakes just don't like to be " forced' into anything. In the wild that means certain death.
I use a large Rubbermaid tub as a soak tub. I place a half of a cinderblock as a hide area in the middle of the water and let Nature take its course. They instinctivley head for the hide area.
I also agree with the live food issue. Not only can rodents administer a nasty bite, but frozen food seems to reduce aggressiveness.
But then again, what the heck do I know?