problem with rigid body

iop iop : i try to do an animation of this : http://www.blender.org/cms/typo3temp/pics/6f6f0af7c8.jpg

For the fluids it’s ok , i can make the same effect easily , but I want that an object hit the glass > My first problem is that the glass designed as a rigid body is Vibrating on my floor > My second probleme is that I succeeded not to have a realistic choc with a sphere (for exemple) designed as a rigid body. I tested with SENSORS CONTROLLERS and ACTUATORS but …

Can you tell me how i can have a realistic falling of the glass?
thanks

(scuse my bad-english)