In addition to following the instructions in the doc you need to enable WebDAV on the web server – this is done via the “Add/Remove Windows Component” applet. Go under IIS and select WebDav Publishing. Also if using a self-signed cert make sure you log in with slxservice (or whatever user is doing the sync service) and install the certificate (just connect to the ssl website with IE while logged in as slxservice and install the cert)