I don't know about this kind of workflow, but you might want to explore the XFL file format.
Last year I have leveraged XFL for integration of After Effects motions in a Flex project:
After Effects > export to XFL
Flash Professional > import of XFL, export as motion XML files
Flex > read the XML files and playback motions
Now, you can also export to XFL from In Design:
Since XFL is a XML file, you could read it and parse it in Flex.
Another option would be to import the XFL into Flash and turn the templates into Flex components.