Convert Unity 2.x asset bundles to Unity 3.x

Hello! We are currently trying to upgrade some old levels to the current version of Unity 3.0 used by our game…

To do this, we are using the following process:

Import the levels into Unity 2, and save them to scenes
Upgrade the project to Unity 3,
And finally export the asset bundles back out.

But, the problem comes in at step one…

You see, if we try to import the scene in an editor script… nothing happens
If we run the same import code at runtime however, the world imports just fine – But because it’s runtime, there is no way to save it to project scenes!

So, there you have my dilemma, and that brings me to my question:

How can I save asset bundled scenes (as well as their corresponding assets) permanently to a Unity 2 project? Is this impossible? If it is impossible, is there another way to upgrade my asset bundles?

You can not convert asset bundles nor can you even extract all the required data from the bundles as they do not contain all informations (part of the stuff like shaders and scripts are part of the project itself only)

You need to use the original project, convert that one to Unity 3 (and then 4 unless you want to repeat the procedure in 4 months), and then export the asset bundles from there.