versinoning on page not working

When trying to reportduce this scenario :

Modify and restore contents form container level up to whole web site level (container, page, section and entire web site), for each object modify several fields in both edition and metadata sections, validate it and restore the previous version, restore again the second version, verify its contents are restored correctly, remodify it again and revalidate it, restore again the previous version...
On container level test the possibility to choose 'Date range' and verify the displayed list is correct.
On page level test all these 3 versioning options:
• Undo staging modification with live content
• Restore archived content
1. Exact Restore
2. Partial Restore
• Restore deleted page

I cannot preceed with the last screen as it gets stuck on "proceed to step 3". This is due to the lack of sitemap on the engine