For some reason my dogs always have to be taught to stay out of the water, at least in January.
BBS2, is your new buddy small enough to carry out into the water and let go of? Maybe that will jump start the jumping in without traumatising them. Mine (all 75 pound of him) loves to have daddy hold him up for a minute in the water after chasing the ball for a half hour or so. I feel like I'm giving swimming lessons!