As it is the action changing the jump force simply doesn't work. You can create an action set to changing the jump force (for example from +20 to +50) but the only effect it has is to make the char immobile for the duration of the action. This exact same scenario can be recreated in BB1 and then when exported to BB2 the action works as it is supposed to (changes jump force). I've just tested it in the new BB2 beta2 and it still does not work correctly.
