Good one!
That really wasn't a huge problem for me, as I got into both softball and baseball umpiring at about the same time. (Just a couple years earlier for baseball, so that is where I had my first meetings, classes and clinics). I was a softball coach for about 15 years before I ever worked my first baseball game.
It wasn't like I'd done baseball for years and years before deciding to get into softball. In other words, I didn't have to "unlearn" a lot about either sport before getting up to speed in the other.
When I started out, I also visited a handful of baseball forums and had the pleasure of getting beat-up on those by a whole different bunch of guys!