Cannot export as PDF a given revision of a page

Steps to reproduce:

• Go on a document with multiple revisions
• Go on an older version of a document
• Export the document as PDF or XAR for example
• Notice the PDF export:
  • The exported document contains the latest version of the document
  • In the export preview the URL contains &rev=[version number], but it doesn't take the parameter in to account to export the proper version.
• Import the XAR so you can verify the imported content:
  • the XAR contains the changes at the last revision