I use that workflow all the time.
1. Cut in PrP.
2. Send a clip to AE.
3. Edit in AE and Save.
4. Go back to PrP and AE DL clip is on the timeline.
What version of CS are you using?
How about details on your edit system.
Tom Daigon
PrP / After Effects Editor
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid
http://www.hdshotsandcuts.com