Render clips the particles

Hi!
I have a workspace setup for extreme pixel ratio of 3500 X 768 (for a screen of 8 by 2 meters) and I have one layer of a footage together with a solid with particles on it (mist). every output of these layers are set to the right pixel output but when I rendered it out it clipped the particles and instead of coming in from the left side of the 3500 they appear alot further in. Now, is there something I have missed here, some clipping function, an output setting?
Thanks!
//Andreas