Well, I'm not currently working on SharePoint, that's why my posts are so rare ... But I have a look at what's happening.

And there it is ! The SPout/SPin manifest file is decribed in this document from Microsoft.

What to do with it ?

• Create your own "Exporter" (from any technology) and use SPin to import into SharePoint 2003.
• Custom the SPout-generated xml file and use SPin to import into SharePoint 2003.

An alternative (with best and worse points) to the Extractors/Importers.

Enjoy !