What I've been doing is creating in 8, rendering to avi, and then using the avi clip in 7. That's not to say that there aren't other ways of accomplishing this, but it works for me.
You could also download the debug mode frame server and then just render to the frameserver avi and leave it all open and put that video on yor timeline ( that will allow you to do it w/o spacerequirements of uncompressed avi's (if space is problem for you, though titling xids shouldn't take up too much space).