No, XDCAM HD didn't even exist when After Effects 7 was released.
XDCAM EX/HD support was added in After Effects CS4.
And now? I'm trying to import the same footage to after effects on a Windows PC and getting a white screen...
In older versions i've used the MC codec and placed it in the root of after effects. But with the new version van CC it was already installed... But it doesn't work. (on premiere CC it does work correctly).
When I replace this codec with my older one, I'm getting a pluging error.