Hi Fernando. There is a bit of misunderstanding here. I didn't say anything about not being able to export separate passes. I use that feature all the time. I also export mattes using the Object ID and the usual Compositing Nodes.
What I said was that there is no way for the exporter to link to those additional passes. That's because there is no Python support in Blender 2.49 to query the compositing nodes.
The AEE links automatically to the exported Combined pass. For the additional passes it creates AE placeholders but it cannot link to the actual footage.
With Blender 2.5 there is more extensive support for Python, including the Node system. When the AEE will be ported to 2.5 it will link directly to the additional passes.
Hope this clarifies the issue.
Cheers!
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Paolo Ciccone
Pret-A-3D
http://www.preta3d.com
http://www.paolociccone.com