[ODE] how to stopbody enabling by joint

[Krystian Ligenza]

here is how fixed joint behave:

http://www.kxl.com.pl/ODE/KxL_Rope_platform_jointFixed.avi

everything would be ok, except this pull down (I rotate, platform goes 
down. I move side, same thing). Any idea to make it correct?

Thanks,
Krystian