I managed to get my MX02 CS5.5 plugin to work with AE CS6. I'm not sure if this will work with other Matrox cards but it probably will. This is a non supported hack, but appears to work fine for now.

Open: programmes files/adobe/AECS5.5/support files/plugins and locate this little file: mveaepreviewcs5.aex  Copy and paste this file to the identical AECS6 plugins folder, then rename the file mveaepreviewcs6.aex Start AECS6 and voila

This is not an approved method, but will work until the new drivers are released. Please undertake this at your own risk.
Still looking for a way to access the Matrox with PPro - but not much hope as so much has changed.