Meh, maybe one day someone will allow empathy to determine if a droid or ranger gets to take home a psuedo-dragon No - its just as u say, a succesful empathy check means the animal doesn't attack, period. I haven't done the nitty gritty yet, but i intend to fiddle it so that the animal 'resets' after a period (probably an hour) and in that time, as u say, it won't attack the party.
Okay, cool. I was envisioning a weird situation where the animal would leave the ranger alone and he'd be forced to sit on the sidelines while the rest of the party got mauled for fear of losing his powers.