The CMIS integration works, you need to set up the CMIS binding. These are possible to define only if you enable “Use LibreOffice dialogs” in Tools->Options->LibreOffice->General.
After you do that, you can go into File Open Dialog (File->Open) and click onto tiny ellipse button (Connect to server). Set name of the server, choose type “CMIS”, Server Type “Alfresco 4”, put in server name, choose repository.
I am still yet to learn how to make Alfresco’s “Edit online” button on documents to launch LibreOffice. Please write in comments how to do that (if possible).