How do I connect to Dropbox, Box and Google Drive?

I got connected just fine to S3 and my ftps are working fine but I can't figure out how to connect to my Dropbox, Box and Google Drive accounts. I looked through the Knowledge Base but I only saw some unfamiliar webDAVs and instructions on putting the favorites into an already synchronized Dropbox folder...
Thanks in advance,

These proprietary protocols are not supported.