It does work but has some realy strange effects sometimes 
but i have a new problem (also in dynamics)
i wand a sphere to balance up and down or sideways around one point in space
I did get it to work (but with a problem)
What did i do?
wel
i took a sphere an moved it up a bit
then i put two Null's in the sen and moved one to the right
i gave the center null an direction canstraint to the other null and an up vector constraint to the sphere
then i put phisical properties on the sphere an gave the grafaty icon an oriontation constraint to to center null
this lets the grafity always point from the sphere like i want to
BUT (here comes the problem)
the sphere is moving futher and futher away from they grafity pont (its faling faster ant faster) but i dont wand that i want it stationairy
how can i fix this????????