Hi there! Is it possible to bring video into flash and have a portion of that video be transparent?

I am working on an intro for a client with a big vault door that opens to the main navigation page.

The vault door is a .mov that the client picked out. Right now I have the vault chroma keyed to open to an image of the main page, then when the sequence is finished, I have the real main page pop up, but with the compression, it looks super artifacted and blurry and the client is upset. ARGH.

Anyone have any ideas here??