How to get data from XWiki 0.9.840 working on XWiki 1.0 Beta 1?

Hi, we have a XWiki 0.9.840 instance running with Postgres 8.1 and we would like to test the new 1.0b1 release with our existing wikis. How could we transfer the data between the old version and the new? The installation docs don't describe a proper way and just copying the dump of the old data to another database and running XWiki with this db doesn't work, too. The Hibernate mappings seem to have changed. What could we do? Our wiki has grown for about half a year and copying the data manually would take really long. Does there any kind of filter exist? Nevertheless, the 1.0b1 looks really nice. You did a really great work. :) I hope I'll be able to run the 1.0-series soon. :) Best regards, Fabian.