it is possible to get them off live foods, and that should definitely be attempted as they are quite susceptible to bacterial infections transmitted by feeders (along with ich). i've done this with several specimens...it works similarly to gars, but takes a bit more patience depending on the individual.
i would definitely keep them no warmer than room temp as this will help keep away any infections as well.
for feeding, get them accustomed to noting something being dropped from the surface...whether you start off with rosies or some other feeder. just drop the food in and get him conditioned to strike at what you drop in. once the fish is conditioned try dropping in raw shrimp or raw fish. it should eventually catch on, and it will take the non-live food. again, this can take some patience as these fish are even more visually/movement oriented than gars.
with a little patience you can get them onto cooked shrimp at which point they will do great...and should generally be kept in a species only tank as they can be quite aggressive with other tankmates while feeding (accidently clipping fins, etc), and they are easily picked on by other fishes (especially sunfishes cannot resist their constantly moving pectoral fins).
great fish for sure, i'm hoping to get one or two this summer during our lake surveys. let me know if you need further info, and best of luck!--
--solomon