XWikiPreferences and 0.9.840

Hi, I migraded a mysql based 0.9.840 XWiki to 1.0B3. I need to keep the old Style/Layout. Unfortunately, I do not get the XWikiPreferences Page. Therefore, I cannot import/export admin pages. Calling http://localhost:8001/xwiki/bin/admin/XWiki/XWikiPreferences leads to a strange Page containing just 'Hello'. After migrating the configuration und preferences pagesare still like in 0.9.840. How can I get the XWikiPreferences page and/or upgrade the admin pages to use the new features? Regards, G Leeb