PNG with Alpha into FCP..

Hi.

I have a 15 minute movie that I've edited in FCP7.

The transitions and text are animated on After Effects, exported in 1920x1080 Quicktime PNG codec, because of the need of an alpha channel for transparency.

I import it into a timeline that is 1920x1080 Apple ProRes 422 configured, because the timeline is mostly from 7D and 5D footage converted from MPEG Streamclip.

The result I get is that the text and lines from the PNG-codec .mov have some "cracks", not near as smooth as in the PNG compression. The example is below:

PNG codec mov exported from AE:

http://oi42.tinypic.com/65ww1h.jpg

Inside FCP and FCP-exported movie:

http://oi43.tinypic.com/290ykqr.jpg

How can I get Final Cut to export or interpret the footage correctly?

Or should I export it differently from AE?

Thanks!