Not all the documents are imported when using a XAR generated by WikiStream from Confluence

Steps to reproduce:

1. Install the WikiStream Application and the WikiStream Confluence XML module
2. Go to WikiStream.WebHome and pick "Confluence XML import stream (confluence+xml)" for the Input Type and "XAR output stream (xwiki+xar/1.1)" for the Output Type
3. Type in the source of your zip in this format:

   file:D:\xwiki\confluence.zip

   in the Source field from the "INPUT CONFIGURATION"

4. Type in the target in this format:

   file:D:\xwiki\confluence.xar

   in the Target field from the "OUTPUT CONFIGURATION"

5. Click Convert
6. Go to Administration -> Import & import the previously generated XAR

You'll see this message:

    1 Document(s) installed
    0 Document(s) skipped
    2 Document(s) with error

and if you go to Demonstration Space's document index you'll only see WebHome listed.

If instead of "XAR output stream (xwiki+xar/1.1)" you pick "XWiki instance output stream" on step 2 the 2 pages are properly imported.
I've attached the zip I used for testing.