there is no OOTB sync provider for SharePoint so you will have to write your own. the custom provider will need to interact with the web services exposed by SharePoint as indicated in the blog post you mentioned above.
check out how to write a custom provider in the documentation. you may also check out these samples to get an idea how to sync files with a custom provider:
http://code.msdn.microsoft.com/Synchronizing-Files-to-a14ecf57 - File Sync to Windows Azure Storage
http://code.msdn.microsoft.com/File-Sync-with-Simple-c497bf87 - File Sync to Custom Provider