I got it guys...follow below mentioned settings...
Use 'Chroma Key' to remove background & export as .mov file.

Export Movie Settings:

Compressor - Animation;
Color Depth - Millions+ of colors;

Keyframe and Rendering:
Tick 'Deinterlace Video Footage’

Before you try this, install flash 8 for latest codec/alpha channel support & QuickTime latest version.
instead of animation i have been using tga and not clicking the deinterlace (which i will try now). dont know what difference having the latest quicktime makes so i will check that out as well.

all the other settings the same but you have to play around with the chroma key settings (similarity, blend etc.) for the best results.
Community content is available under CC-BY-SA unless otherwise noted.