Urgent particle help!!!!!

Hello Sir
I am facing a small difficulty.
As you would find in the max file attached that
i have a particle system emitting particles inside a box.
All the objects including the particle system are attached to the Dummy.
The particles are falling straight downwards and are contained inside the box
(deflector).
But as soon as the dummy shifts its position the particles inside the box gets
disturbed.
I would want the straight motion of the particles to continue inside the box
regardless of t
he
dummy (along with all the other objects) changing its position.
The particles should keep falling straight inside the box.
Thanks in advance.