Unable to import a XAR generated by the Wiki Stream Confluence Importer

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. Try to import the previously created XAR

When you want to import the XAR in XWiki you get a message saying that there aren't any documents to import. I've noticed there's no package.xml inside the archive on a Mac. On Windows I couldn't view/extract files from the XAR.