Upgrading ZevenOS 3.0 to Natty Narwahl

I had ZevenOS 3.0 working fine on my EeePC901 with compiz, AWN and Conky all performing perfectly.
But every time I booted to ZevenOS, I got a message inviting me to upgrade to Natty Narwhal. Of course, I can never resist such inducements so I finally succumbed and did the upgrade which took close to 7 hours.

Even though I have Ubuntu Natty working absolutely fine on the very same machine, the upgrade did not go smoothly. Exactly what I did, and the problems I experienced, are described in this forum thread.

In summary:
1. You MUST use the login screen to select a suitable session (avoid automatic login initially)
2. The only session I found to be completely usable was Unity-2D (although no 3D effects)
3. However, no Haiku desktop so it looks just like Ubuntu Natty